Jasper – TumbleStone

“Simply the Best” – Third Stone Added to TumbleStoneTwo’s Hall of Fame

Today it was reported that Tina Turner, Queen of Rock’n’Roll, had passed away in Switzerland after a long illness, aged 83. This has prompted me to write this Post in memory and respect, and to feature her song “The Best” to mark the addition of a third stone to TumbleStoneTwo’s Hall of Fame.

“The Best” is perhaps Tina Turner’s most well-known song in New Zealand and Australia as it was famously used to promote the Australian National Rugby League (NRL) competition in 1990 – see this YouTube video. Initially, in 1989 Turner’s “What You See Is What You Get” was used by the NRL – see this YouTube video. Its amazing success led to “The Best” campaign the following year. In 1993, Turner performed live at the NRL Grand Final. She then re-recorded “The Best” in 1993 with Australian musician Jimmy Barnes (video below). “It’s a song that has stood the test of time and is now synonymous with rugby league in this country” (ABC News). It helped to change the image and popularity of the NRL and was part of maybe the most successful sporting advertising campaign in Australia (NRL.com).

Tina Turner was inducted into the Rock & Roll Hall of Fame twice, in 1991 with her then-husband Ike Turner and again in 2021 as a solo performer. TumbleStoneTwo’s Hall of Fame contains simply the best of the stones I have found and polished. The first inductee was an agatised fossil coral from Gemstone Beach. The second was a mossy jasper from Kakanui’s Seadown Beach. The third stone added today to the Hall of Fame is a hematite jasper I found on the beach at Timaru South in March 2022. It was just a bit too big for me to tumble so I asked my friend Tracey Kidd who lives near Christchurch if she would give it a go – she has a tumbling barrel larger than my largest 12lb one. Tracey went ahead and tumbled it successfully. The shine on it is so good that it is difficult to photograph without reflections interfering, even in bright direct sunlight.

The stone as found on the beach in March 2022.

The polished stone.

Close-up of polished stone.

The polished stone is 7.5 cm long and heavy – it weighs 20 grams. It has a few small holes in it as it started out in a bit of a mangled condition. But it polished very well, thanks to Tracey’s work.

January 2022, Stone of the Day #19 – Tiny Stone: A Gemstone Beach Jasper?

I once mentioned in a Post on “small stones” that they are invaluable to the tumble polisher. In a rotating barrel, small stones “carry” the grit or polish to the larger stones, fill up the spaces between them, and balance the load. Some small stones are striking in their pattern or colour or shape, and are valuable in their own right as interesting and beautiful stones. However, they do get smaller after each stage. This tiny stone from Gemstone Beach is an example of the exquisite character that a small stone can have:

The stone is 2 cms long and 1.5 cms wide and 0.5 cm thick (see photo at bottom of page for comparison with some other Stones of the Day). It might be a jasper, though sometimes we too often identify a stone as jasper simply because of the dark red colour when other kinds of stones, such as quartzites, can also be that colour due to the presence of iron oxides. The stone has been tumbled in 400 grit, then 600 grit. After 17 days in tin oxide tumble polish, it was burnished for nine days in borax. The extra tumble in 600 grit is an experiment I have been conducting recently for especially jaspers and stones consisting of more than one mineral, to try to get the whole pre-polish surface as smooth as possible. I have also been lengthening the times of each stage to see if this improves the final product. This tiny stone has polished very well.

Other side of Stone #19.

What attracted my eye to this small stone on the beach was the light red, almost pink, splash of colour at one end. Polishing has clarified the whole stone and revealed the clouds of colour throughout it. What has also become apparent is a small stress offset (faultline) that has been filled in by some kind of silica (could be quartz):

The small faultline in Stone #19.

The small faultline in Stone #19.

The “small stones” of an earlier Post https://tumblestoneblog.wordpress.com/2019/06/21/little-things-the-value-of-small-stones.

Stone #19 compared for size to other Stones of the Day.

The Index to the January 2022 Stone of the Day Series is here.

January 2022, Stone of the Day #8 – A Kakanui Brecciated Jasper

Another nice stone found on a North Otago beach, near Kakanui, sometime during the last 18 months and finally polished in December 2021:

It is 4.5 cms long, 4 cms wide and 2 cms deep, a good size. I tumbled the stone initially in 400 grit for 10 days then in 600 grit for 14 days. I have recently been adding this 600 stage especially for jaspers. It then spent 14 days in tin oxide polish and was burnished in borax for three days. This type of jasper can be found on many beaches in New Zealand, and it usually polishes very well:

The other side of Stone #8.

I used two main sources to confirm my strong suspicion that this is most likely brecciated jasper. First, I referred to Patti Polk’s book, “Collecting Rocks, Gems and Minerals” (3rd edition, published in 2016). Polk is a notable agate collector from the USA and her book has a well-illustrated section on jasper. One page is on brecciated jasper and some of the examples shown there confirm the identity of Stone #8:

Page 114, Patti Polk (2016), “Collecting Rocks, Gems and Minerals”

Secondly, Wikipedia turned out to have a couple of useful photos in its entry on “Jasper”:

Source: https://en.wikipedia.org/wiki/Jasper#/media/File:Jasper.pebble.600pix.bkg.jpg

Source: https://en.wikipedia.org/wiki/Jasper#/media/File:Cut_and_oiled_yellow_jasper_3.JPG

https://en.wikipedia.org/wiki/Jasper

I have found a small number of brecciated jasper stones at Kakanui before and one is featured on the January page of my 2022 TumbleStone calendar:

January page of 2022 TumbleStone Calendar

Close-up of brecciated jasper from 2022 Calendar

Another Kakanui brecciated jasper, found June 2021

Another Kakanui brecciated jasper, found March 2021

Another Kakanui brecciated jasper, found June 2021

Stone of the Day #9 is here. The Index to the January 2022 Stone of the Day Series is here.

January 2022, Stone of the Day #4 – An Orbicular Hematite Jasper from Gemstone Beach

This small orbicular hematite jasper was found on Gemstone Beach early in 2021. I have found a limited number of other such stones there and at Kakanui, though this might be the biggest. It is still quite small, being 3.5 cms long by 3 cms wide by 1.5 cms deep. As well as generally being small stones, orbicular jaspers often have cracks and pits in them so that I have not yet been able to produce a fully smooth polished one. This is one of the best, with only one very thin crack and a three tiny pits marring its smoothness.

Such stones often get a little more time in 400 grit from me, often repeating the stage, before going on to be polished, to try to minimise the cracks and holes. As I noted in a previous Post about a similar stone, Mindat states that orbicular jasper is “a highly silicified rhyolite or tuff that has quartz and feldspar crystallized into radial aggregates of needle-like crystals forming orbicular (spherical) structures”. If the orbs are red, we tend to call it “poppy jasper”.

The other side of Stone #4.

A very similar type of stone is “brecciated jasper” – see the “H is for Hematite Jasper ” entry in this Post for information about this small brecciated jasper I found on Gemstone Beach in February 2021 (compared below with a photo of another small orbicular jasper I found on Gemstone Beach on 22 June 2021):

Brecciated hematite jasper.

Another small orbicular jasper found on Gemstone Beach, 22 June 2021

Hematite is an iron oxide compound widely found in rocks and soils. It occurs naturally in a variety of colours – black to silver-gray, brown to reddish-brown, and red. It is the silvery gray and black that are most noticeable in Stone #4.

Stone of the Day #5 is here. The Index to the January 2022 Stone of the Day Series is here.

“O” is for “Opaque Orepuki Orbicular Jasper” and “P” is for “Planet in a Pebble”

J is for (Picture) Jasper

K is for Kai Iwi Beach Stone

L is for Leithfield Beach petrified wood

M is for Muscovite Mica from Joyce Bay

N is for November in the Calendar

The following are my Posts for “O” and “P” in the alphabetical series of a Facebook Group I belong to, “New Zealand Lapidary, Rocks, Minerals, Fossils”. The first Posts in this Series can be found here.

“O” is for “Opaque Orepuki Orbicular Jasper” – This small (thumb-nail sized) tumble-polished orbicular hematite jasper was found on Gemstone Beach, just a kilometre west of the small Southland town of Orepuki.

A small orbicular hematite jasper from Gemstone Beach, Orepuki.

Jasper is an “opaque” rock. Opaqueness is one of the three main ways of classifying how light passes through a stone or rock. “Transparent” means light passes through easily (e.g., clear quartz); “translucent” means only limited light is able to pass through the stone, so that an object held behind it would look fuzzy; “opaque” means light does not pass through the stone at all. Jasper is an opaque form of chalcedony, a cryptocrystalline form of silica. Chalcedony itself is usually described as semi-transparent or translucent. The incorporation of minerals, such as iron oxides, provides jasper with its opaque nature. “Orbicular” jasper is a variety of jasper which contains orbs or spherical features. Mindat states it is “a highly silicified rhyolite or tuff that has quartz and feldspar crystallized into radial aggregates of needle-like crystals forming orbicular (spherical) structures”. If the orbs are red, we tend to call it “poppy jasper”. One type of orbicular jasper is “ocean jasper”, a trademarked name for a multi-coloured stone from Madagascar. Sometimes it can be difficult to distinguish between orbicular and some forms of brecciated jasper.

Page 72 of A.B. Busbey, R.C. Coenraads, D. Root and P. Willis, 2013, “Rocks and Fossils”.

Part of page 72 of A.B. Busbey, R.C. Coenraads, D. Root and P. Willis, 2013, “Rocks and Fossils”.

Page 122 of P. Polk (2016), “Collecting Rocks, Gems and Minerals: Identification, Values, Lapidary Uses”.

Part of page 122 of P. Polk (2016), “Collecting Rocks, Gems and Minerals: Identification, Values, Lapidary Uses”.

Www.mindat.org/min-27171.html

Ocean jasper. https://www.entertheearth.com/the-geology-varieties-and-history-of-ocean-jasper-part-one/?fbclid=IwAR3sBTOMAxOzoMR1I5G76-1Yujb0ZZqpdR4PTCsqWum0o4XGYOLtHVPOVQY

A similar small jasper stone from Gemstone Beach, could be brecciated rather than orbicular, difficult to tell clearly.

My stone was found on Gemstone Beach near Orepuki, which Wikipedia describes as “a small country township on the coast of Te Waewae Bay, some 20 minutes from Riverton, 15 minutes from Tuatapere and 50 minutes from Invercargill”. Once a thriving settlement of 3000 people, with gold mining, oil shale, and flax being big industries, today about 60 people live there, with the tavern and café being the only two town businesses (http://www.stuff.co.nz/…/orepuki-much-more-than-just-a…). The Wikipedia entry on Orepuki mentions nearby Gemstone Beach, even noting that “this wild beach contains semi-precious gemstones such as… orbicular jasper” (https://en.wikipedia.org/wiki/Orepuki). The photo below of the sweep of Te Waewae Bay, looking west past Gemstone Beach, was taken at the spot marked with a red X on the satellite map, on the eastern outskirts of Orepuki.

Gemstone Beach scene.

Looking west along the sweep of Te Waewae Bay. Photo taken from eastern outskirts of Orepuki, with Gemstone Beach being 1 to 2 kms from this point. The site from which the photo was taken is marked on the bottom left of the next photo.

Orepuki and Gemstone Beach on Google Maps http://www.google.co.nz/…/@-46.2811355…/data=!3m1!1e3. Red X at lower left marks spot from which previous photo was taken.

Page on oil shale mining at Orepuki on 19th century – page 19 of Heritage Trail booklet.

Page on Gemstone Beach area – page 25 of Heritage Trail booklet.

Booklet I bought from Riverton/Aparima Museum Shop.

“P” is for “Planet in a Pebble” – This small polished grey stone is from Gemstone Beach. Like a handful of other stones I have found, it is possible to imagine that you are looking down on a planet from space, with lots of stuff going on in the atmosphere or on the liquid surface.

“The Planet in a Pebble” is also the title of a book published in 2010 by the Polish geologist Jan Zalasiewicz, sub-titled “A Journey into Earth’s Deep History”. In this fascinating and engaging book, he tells the story of a pebble’s history, stretching back billions of years. In Chapter One, “Stardust”, he points out how, at the atomic level, a pebble and a person share the same kind of atoms – we are kin. And a pebble is a microcosm of the Universe, made up of that which goes back to the singularity of the beginning of everything. Zalasiewicz writes on page 7, “The pebble, in this respect, is as deep a mystery as is everything else in the Universe. How did the matter of that pebble, and of the…hills it was torn from, and of the world it sits atop – and of the Solar System and of the Milky Way, and of countless galaxies near and far – manage to unpack itself from a point: a ‘singularity’, as many think, of no size at all?” As I mentioned in a blog post I wrote five years ago, a pebble is made of stardust and in it we encounter not only our selves but also the depths of the Earth and the heights of the heavens. Looking down is a way of looking up. Looking into a stone is also to glance across deep dark space and even time. In a stone we make contact with that which is closest to home as well as that which is furthest away. The photos of the stone below include colourful experimental ones, playing around with Picasa software.

See here for the next Post in this Series, and here for the Series Index.

“M” is for “Muscovite Mica from Joyce Bay” and “N” is for “November in the Calendar”

H is for Hematite Jasper

I is for Ichnogenus Protovirgularia

J is for (Picture) Jasper

K is for Kai Iwi Beach Stone

L is for Leithfield Beach petrified wood

The following are my Posts for “M” and “N” in the alphabetical series of a Facebook Group I belong to, “New Zealand Lapidary, Rocks, Minerals, Fossils”. The first Posts in this Series can be found here.

“M” is for “Muscovite Mica” from Joyce Bay, Charleston. Thirty kilometres south of Westport is the town of Charleston and its small twin bays, Constant Bay and Joyce Bay. Constant Bay was named after the ketch “Constant” whose Captain, Charles Bonner, in the mid-1860s managed to squeeze the boat into the tiny bay, bringing supplies for the town that had sprung up due to the discovery of gold.

The small West Coast town of Charleston, with nearby Joyce Bay (Constant Bay is right next to Joyce Bay). Source: https://mapcarta.com/24776122

Postcard showing Charleston with Joyce Bay to left and Constant Bay to right.

The rocks that line the shore of these bays contain pegmatites, large veins of quartz with masses of mica in them. A pegmatite is a crystalline igneous rock containing a variety of crystals formed by slow crystallization at high temperature and pressure at depth, exhibiting large interlocking crystals.

Part of a pegmatite in the two small bays.

Close-up of pegmatite – lots of mica among the quartz!

When I visited the area in 2018, at the northern end of Joyce Bay I came across some stones from a vein that must have been almost pure mica. I chose this small boulder-sized rock to bring home, and it has sat in the lounge since, one of the very few non-tumbling stones I have kept.

Found at Joyce Bay, this stone consists of at least 90% muscovite mica.

There is so much mica in the rocks around Constant and Joyce Bays that the sea sparkles with it.

The two most common forms of mica are the silvery muscovite and the darker biotite. Mica minerals form large, flat sheets due to their atomic structure. Strong silicon-oxygen bonds extend outwards in two directions while the third direction only has weak bonds with large, low charge atoms in the space. One thin sheet is transparent and almost colourless, feeling like flexible plastic. Sheets of muscovite five metres by three metres have been found in Nellore, India. Technically, muscovite mica is composed of potassium aluminum silicate hydroxide fluoride. The name “muscovite” comes from Muscovy-glass, a name given to the mineral in Elizabethan England due to its use in medieval Russia (Muscovy region) as a cheaper alternative to glass in windows.

From page on “Pegmatite” – page 36 of R. L. Bonewitz, “Rocks and Minerals: The Definitive Visual Guide”.

Page 261 of R. L. Bonewitz, “Rocks and Minerals: The Definitive Visual Guide”.

17th century Russian windows made from sheets of mica – https://the-earth-story.com/post/142287548341/mica-window-these-russian-windows-are-over-200?fbclid=IwAR3bcSViP_uosW8QONuvt9e6yYNW9-50tHwHyjHHTiib0q94JQKoY-B7Zh0

Sheets of muscovite have high heat and electrical insulating properties and are used in the manufacture of many electrical components. Muscovite sheets were used for kitchen oven windows before synthetic materials replaced them. Muscovite can form during the metamorphism of argillaceous rocks. The heat and pressure of metamorphism transforms clay minerals into tiny grains of mica which enlarge as metamorphism progresses. Small flakes of mica are often a component of a wide range of part of different rocks. For example, muscovite occurs as isolated grains in schist and gneiss, and it can be abundant enough that the rocks are called “mica schist” or “micaceous gneiss”. Jocelyn Thornton in her “Field Guide to New Zealand Geology” (2003) writes on page 103: “Hidden in the gorse-covered stretch between Charleston and Constant Bay is a pegmatite that was once mined for mica; the outcrop still contains large crystals of muscovite mica.” In “Geology of the Greymouth Area” (2002) by GNI, page 43, it is noted that “a small amount of mica was mined in 1911-12 from a pegmatite near Constant Bay, but the grade is low.”

Charleston mica mine https://natlib.govt.nz/records/22415334?search[i][subject_authority_id]=-3477&search[path]=items&fbclid=IwAR3hQzJ9Pr6-Aw-UHtczoN8hVmrCPeV7-0mC5bIK9jrG32nRgYBsPo0WTS0#content

Charleston mica mine https://natlib.govt.nz/records/22415334?search%5Bi%5D%5Bsubject_authority_id%5D=-3477&search%5Bpath%5D=items&fbclid=IwAR3hQzJ9Pr6-Aw-UHtczoN8hVmrCPeV7-0mC5bIK9jrG32nRgYBsPo0WTS0#content

https://westcoast.recollect.co.nz/nodes/view/1667

For more on muscovite mica and its uses, see here.

“N” is for “November” in the Calendar – Each year I produce a customised wall calendar, using an online site, with stones or beaches or tumble-polishing as the theme. This is the month of November in my 2021 calendar. The month’s theme is “Stones from Leithfield Beach, Canterbury” with close-ups of four un-polished stones. One of the four stones shown here is a red and yellow jasper, collected in August 2020.

November’s photos.

One of November’s stones from Leithfield Beach.

November is also usually the month in which I prepare the calendar for the following year.

For the next Post in this Series, see here. For the Series Index, see here.

National Lockdown Number Two: Stone Two

To mark Day Two of this National Lockdown, this is a tumble-polished jasper from Gemstone Beach. It is almost barrel-shaped:

Jasper is often difficult to tumble successfully as it is often a little brittle. Jasper can also have tiny cracks or holes that can be too deep to remove without making the stone too small.

This stone feels very smooth but the close-up photos reveal a number of tiny imperfections and rough spots.

Despite this, the stone also shows the complexity and beauty of this kind of jasper.

Another 11 cases of Covid-19 were identified in the community in New Zealand today, as reported at the 1 pm government news briefing. All but an aircrew member, returning from Japan, appear to be linked to the initial case identified two days ago, with all cases being in Auckland. Contact tracing and widespread testing is being undertaken. Through genomic sequencing, the source of the cluster infection has been traced to a traveler from Sydney in managed isolation.

Stone of the Day #3 is here.

“I” is for “Ichnogenus Protovirgularia” and “J” is for “(Picture) Jasper”

D is for Dendrites

E is for Entrance

F is for Fossil Worm Cast

G is for Green Hydrogrossular

H is for Hematite Jasper

A Facebook Group I belong to, “New Zealand Lapidary, Rocks, Minerals, Fossils”, invited its members to submit photos each week of a stone, mineral or fossil in their collection that starts with a letter of the alphabet. The first Posts in this Series can be found here. The following are my Posts for “I” and “J”.

“I” is for “Ichnogenus Protovirgularia”. This argillite stone from Gemstone Beach contains a trace fossil shape that has been identified by a trace fossil researcher as belonging to the Ichnogenus Protovirgularia.

A trace fossil is an “ichnofossil” – they are identified by their shapes (not by what made the shapes as this may not always be known). The term is derived from the Greek word “ichnites” meaning “footprint”. An “ichnogenus” is a group of trace fossils with similar characteristics (a “genus” is an intermediate category between “species” and “family”). Ichnogenus Protovirgularia are trace fossil shapes consisting of “a small keel-like trail which is composed of an elevated median line and lateral wedge-shaped appendages alternating on both sides”, including lines of chevron shapes (as in this stone I found on Gemstone Beach). They were given this name in 1850 by Frederick McCoy, an influential Irish palaeontologist, who believed he was seeing the actual fossil of an ancestor of Virgularia mirabilis, the slender sea-pen, hence the term “proto-virgularia”. It was not until 1958 that the shape was identified instead as a trace fossil (and one which was made by quite a different animal).

Some of the variations of Ichnogenus Protovirgularia. Source: www.researchgate.net/publication/240776411_Taphonomy_and_Paleoecology_of_the_Bivalve_Trace_Fossil_Protovirgularia_in_Deltaic_Heterolithic_Facies_of_the_Miocene_Chenque_Formation_Patagonia_Argentina

Some of the variations of Ichnogenus Protovirgularia. Source: http://www.researchgate.net/publication/240776411_Taphonomy_and_Paleoecology_of_the_Bivalve_Trace_Fossil_Protovirgularia_in_Deltaic_Heterolithic_Facies_of_the_Miocene_Chenque_Formation_Patagonia_Argentina

The coral spine of the slender sea-pen that McCoy thought that Protovirgularia was the fossil of. Source: https://v3.boldsystems.org/index.php/Taxbrowser_Taxonpage?taxid=726281&fbclid=IwAR2dh9plqzPHUVqTERF97moPqOsUHyV3-0PNsQ4OVmNziC6DXiivmGveGbA

How Seilacher thought Protovirgularia (on right) was produced. Diagram from his book “Trace Fossil Analysis” by Adolf Seilacher (2007), p. 65. However,, note that “Imbrichus” is also similar to the trace fossil on my stone.

It is thought that the trace is usually the product of locomotion (travel movement) produced by small bivalves, a burrow resulting from the rhythmic action of a muscular cleft-foot. On the southern coast, these traces are called worm-casts – it is thought that the casts were left as the worms tunnelled through mud and compacted the (excreted?) sediment behind them. It is not yet clear to me what left the trace on this Gemstone Beach stone, and I am not yet 100% convinced that this trace isn’t something other than Protovirgularia. More details on Ichnogenus Protovirgularia and trace fossil stones can be found here.

“J” is for “(Picture) Jasper” – Picture Jasper from Birdlings Flat.

Jasper is usually described as a form of cryptocrystalline silicon dioxide (quartz), as are a number of other rock types such as chalcedony, agate, carnelian, chrysoprase, chert and flint. “The Photographic Guide to Rocks & Minerals of NZ” defines “cryptocrystalline” as meaning crystals that are less than 0.001 mm in size, too tiny to see even using a hand lens. Jasper is distinguished by incorporating other materials that give it opacity (blocking the light) and colour. The Dorling Kindersley/Smithsonian book, “Rock and Gem”, states: “Brick-red to brownish-red jasper contains hematite; clay gives rise to a yellowish-white or grey, and goethite produces brown or yellow” (see scan of book page below). Names for types of jasper often refer to aspects of their structure or composition – banded, orbicular, moss, brecciated, or jasp-agate. But sometimes names relate to surface appearance and patterns – mottled, spider-web, egg pattern, and picture. Patti Polk, in her book “Collecting Rocks, Gems and Minerals”, defines picture jasper as containing “a dazzling array of colors and exquisitely detailed patterns that resemble skies, mountain vistas, desert landscapes, and forest horizons”. She also refers to “warm tones of tan, gold, yellow, blue, green, and browns all swirled together in strikingly outlined picturesque scenes”.

John Farndon and Steve Parker (2015) “The Illustrated Encyclopedia of Minerals, Rocks & Fossils of the World” p.213

https://teara.govt.nz/en/interactive/5123/chert-flint-and-jasper?fbclid=IwAR11CPAUP8DLyh6UMBXxTgoidS9AdL-ZCxZsXP0_L-nNLJeec8rYARHvQSw

Ronald L. Bonewitz (2015) “Rock and Gem” p.229

Patti Polk (2016) “Collecting Rocks, Gems and Minerals” p.123

I found this small picture jasper on Birdlings Flat about three years ago. Its pastel tones, the contrasts between light and dark, and the way a number of small cracks and fault-lines break up the surface pattern all contribute to its desert-canyon-landscape-picture. [This stone was Stone Eight in the Lockdown Stones of the Day Series.]

For the next Post in this Alphabetical Series, see here. You can find the Index for the Series here.

“G” is for “Green Hydrogrossular Garnet” and “H” is for “Hematite Jasper”

B is for Botryoidal

C is for (Fossil) Coral

D is for Dendrites

E is for Entrance

F is for Fossil Worm Cast

“G” is for “Green Hydrogrossular Garnet from Gemstone Beach”. Found on Gemstone Beach (Orepuki, Southland) early in March 2020, only a couple of hundred metres from the car-park, on the edge of the Taunoa Stream. The “grossular” part of its name is derived from the Latin word for gooseberry, because of the light-green colour of many hydrogrossular stones, like this one. White and brown are two other common colours, with other hues also known.

“H” is for “Hematite Jasper” – This is a small (3 cm long) hematite brecciated jasper stone found on Gemstone Beach, Southland, in February this year, tumble-polished in April.

Polished brecciated hematite jasper stone from Gemstone Beach.

Silvery-gray hematite.

The stone before polishing.

Jocelyn Thornton provides an example of a similar stone from the same beach (see photo below, left) on page 36 of her booklet “Gemstones” .

The following comes from my research to try to understand more about hematite jasper: Jasper is a dense opaque microcrystalline quartz (the crystals are too tiny to be seen by the naked eye). “Jasper” is derived from the Greek word for “spotted stone”, referring to its typical multicoloured, striped, spotted or flamed appearance. Jasper can form in many colours, not just the dark red we usually associate it with. Hematite is a common iron oxide compound widely found in rocks and soils. It occurs naturally in a variety of colours – black to silver-gray, brown to reddish-brown, and red colours. So it is often hematite that also causes the reds in jasper, including the segments of colour seen in brecciated jasper and the “moss” in moss jasper and the “bubbles” in orbicular/poppy jasper (www.quartzpage.de/jasper.html). Mindat has some great photos of jasper and hematite (see photo below, right).

Similar stone in Jocelyn Thornton’s booklet, though this one is orbicular, not brecciated. https://www.onnaturesedge.co.nz/downloads/nzgemstones.pdf

Part of a set of photos from Mindat on hematite and jasper. Source: https://www.mindat.org//photoscroll.php?searchbox=Jasper%2520with%2520Hematite

However, it is the silver-gray hue present in jasper that we tend to call “hematite jasper”. The polishing of the stone I found brought out the silvery-gray hematite shine as well as some green (maybe epidote?). Hematite shows only a very feeble response to a magnetic field and is not noticeably attracted to a magnet.

For the next Post in this Alphabetical Series, see here. The Series Index is here.

FB Group Posts: 21, 22 & 25 June 2021 – Final Fossicks at Gemstone Beach, and a Kakanui Beach Visit

This is the sixth Post on my June 2021 stone collecting trip to the South Island, and is also the 16th Post in the Series of my daily Posts in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. The first Post on my June trip is the Sunday 6 June entry in this Post, and the first in the Facebook Group Series is here.

Monday 21 June 2021: Featuring eight stones from (what I thought was going to be) my last visit to Gemstone Beach this trip. Cold again but sunny and very little wind, good fossicking. Here are five of the stones:

Small dark red jasper.

One of the larger stones I collected.

Another banded argillite, nice and smooth.

Trace fossil stone with long continuous trace.

The Waimeamea River was blocked off by a build-up of stones during the last high tide so I could wander a kilometre further along the beach than previously. Here are the other three stones:

Breccia stone.

Quartz with tiny inclusions.

Near the Waimeamea River mouth, there sitting in front of me was a nice hydrogrossular garnet, one of the few I have found this trip.

It shone brightly among the other dry dull stones.

Waimeamea River blocked off from flowing to the sea. (Froth on the edge.) Walking across the stones to take this photo, I came across the hydrogrossular garnet in the previous photos.

Stones on Gemstone Beach today.

At the edge of the waves.

[Monday 21 June was also the day I made a Post in the Group’s Alphabetical Series – “H” is for “Hematite Jasper…”– see here.]

Tuesday 22 June 2021: Couldn’t resist the temptation to visit Gemstone Beach one more time before leaving tomorrow (despite scheduling today as clean-up and pack-up and load-up the car with stones). Bit of a cold breeze today but a big coat and hood did the trick. Found a few nice small-to-medium-sized hydrogrossular garnets (there have been very few up until today), and the usual colourful and interesting stones. Here are four of today’s finds:

Orbicular (poppy) jasper.

Here are another four of today’s finds:

Gemstone Beach scene today.

One of today’s hydrogrossular garnets.

Trace fossil stone, with iron staining.

And it’s finally farewell to Gemstone Beach for this fossicking trip.

Wednesday 23 June 2021 and Thursday 24 June: Travel days, no beach visits, no posts.

Friday 25 June 2021: Spent just over three hours on Kakanui’s Seadown Beach (North Otago) today. Among my finds were these beach agates and fossil sea floor stones: