Awaruite: The Story of the Second Mineral Described From New Zealand

Awaruite is the second of 13 minerals that have been first described from New Zealand and accepted as valid by the International Mineralogical Association. The first was Taranakite, the subject of a previous Post. This Post tells the story of Awaruite.

Awaruite is a rare natural nickel-iron alloy (Ni3Fe – though web.mineral.com defines it as “Ni2Fe to Ni3Fe”) which was originally found in the early 1880s as water-worn grains in the Gorge River, South Westland. These grains were in two samples of heavy black sand “transmitted to the [government] laboratory through the Secretary for Mines, as having been obtained by some alluvial miners working near Jackson’s Bay, and given to them by the [District] Warden” (quoted from William Skey’s article of 1885). (According to George F. H. Ulrich in an 1890 article on the discovery and distribution of Awaruite, the Warden of the Jackson’s Bay District at the time was a Mr Macfarlane. Ulrich was the first Director of the Otago School of Mines.) The geological source of these grains was traced back to serpentinite rock in the nearby Cascade Valley. Awaruite has since been found in serpentinites elsewhere in the world. 

Awaruite is “silver-white to grayish white”, “strongly magnetic” and has a hardness of 5 on the 10-point Mohs scale. It is malleable and tends to be a little bit softer when its nickel content is a little higher. The presence of nickel means the alloy tends to rust much less readily than iron with very little or no nickel. Below is a model of Awaruite’s crystal structure, from a German online Mineral Atlas www.mineralienatlas.de. If you go to this link and scroll down to find this diagram, it is possible to rotate it in 3D and view other information (if you right click on the linked page, you can translate it into English, if you want).

crystal structure awaruite jjj

Skey’s announcement of Awaruite was in a paper read before the Wellington Philosophical Society on 21 October, 1885, which was then published in a brief two-page piece as Article LXI “On a New Mineral (Awaruite) from Barn Bay” in volume 18 of the Proceedings and Transactions of the New Zealand Institute. (This volume was dated in sequence by cataloguers as 1885 but it actually had a publication date, recorded in the fine print, of May 1886, a point confirmed by James Hector in 1887.)

As noted in a previous Post, William Skey spent 35 years as chemical analyst with the New Zealand Geological Survey under the leadership of James Hector. (In 1865, Hector and Skey had announced the discovery of New Zealand’s first mineral, Taranakite.) Skey argued that Awaruite was a terrestrial rock and did not come from a meteorite. Natural iron-nickel alloys are very rare on Earth and are usually from meteorites. “The even size of the grains, and their number, together with their richness in nickel and apparent uniformity of composition, support the ‘terrestrial’ theory”, he wrote. Skey thought it was the second earth-origin nickel-iron alloy to be discovered but it was really the first, as noted by G.H.F. Ulrich in his 1890 article, “On the discovery, mode of occurrence, and distribution of the nickel-iron alloy, ‘awaruite’ and the rocks of the district on the west coast of the South Island of New Zealand in which it is found” (“Quarterly Journal of the Geological Society of London”, volume 46, pages 619–632). 

The name chosen by Skey, “Awaruite”, was probably taken from Awarua Bay, also known as Big Bay. As Te Ara The Encyclopedia of NZ states, the name is slightly misleading as the mineral does not occur in the Awarua River or Awarua (Big) Bay or even in Barn Bay. As expressed in a 1980 article in Mineralogical Magazine, “The name ‘awaruite’ is therefore to some extent a misnomer’.

Every mineral has a “Type Locality”, which is the locality where the original material came from for the formal definition of the mineral. As mindat.org, the world’s largest non-commercial online mineralogical database, notes, the Type Locality for Awaruite is the Gorge River in Westland. It then states: “The mineral was named after the Awarua River, or the Awarua Bay it flows into, however the species is not found in either site.” Due to this confusion between the name, locality and actual sources of Awaruite, a Government geologist, James Park, (later Director of the Thames School of Mines and Professor of Mining at the Otago School of Mines) visited the area and investigated in 1886, stating the material was to be found in the Gorge and Hope Rivers in gravel wash, and in-situ in serpentinite in the river valleys. The Gorge and Hope Rivers drain the Red Hills Range.

The left map above is “Fig. 1 – Geological sketch-plan and locality map of West Coast, New Zealand, between Jackson’s River and Hollyford Valley, as given by Ulrich (1890) who ascribes it to Paulin and Mueller.” The map second from left above is “Fig. 2 – Geological sketch map of same area as in fig. I as given in Williams (1974)…” These two figures come from the 1980 article in Mineralogical Magazine. The satellite photo second from right is taken from Google Maps and shows the area in Figs 1 & 2, with the red indicator on Gorge River. The satellite photo on the far right above, again from Google Maps, shows the wider geographical context, including Haast and Milford Sound.

Wikipedia notes Awaruite is also known as Josephinite, reflecting the fact that it was independently identified in Josephine County, Oregon, where it is found as placer nuggets in stream channels and masses in serpentinized portions of some of the local rocks. As Skey’s paper containing the name Awaruite was published just prior to the naming of Josephinite in publication, Awaruite became the official name for the mineral and Josephinite a recognised synonym. Mindat.org and web.mineral.com also refer to Josephinite as a synonym for Awaruite. (Two other synonyms are Bobrovskite and Souesite, names given to this alloy at the time when it was found in the Bobrovka River in Russia and in the Fraser River in Canada respectively).

However, against this view, an investigation published in 1979 in the “Geochemical Journal” concluded that Josephinite is a rock name and Awaruite is a mineral name. As a Ohio State University geologist put it, Josephinite is a “crystalline-textured, polymineralic rock” that is dominantly composed of the mineral Awaruite. Josephinite rocks contain an unusual mineral assemblage consisting of Awaruite, Andradite Garnet, Wairuite, minor Pyrrhotite, minor Pentlandite, and other minor minerals. A similar view is put forward, for example,  in a 1976 article in the “American Journal of Science”. 

Josephinite is one of the two official minerals of Oregon, so declared in 2013 “to promote education through the earth sciences, encouraging curiosity and study”. The other is Oregonite. Both Josephinite and Oregonite consist primarily of nickel and iron, and are typically associated with iron meteorites, but as terrestrial minerals are found only in the State of Oregon in the United States, not in any of the other States.

Taranakite: The Story of the First Mineral Described From New Zealand

Taranakite is the first of 13 minerals that have been first described from New Zealand and accepted as valid by the International Mineralogical Association. This is its story.

Taranakite is a fine-grained, cream-coloured phosphate, originally found in veins cutting volcanic rock on the tiny Sugar Loaf Islands (Nga Motu) near New Plymouth in Taranaki. It was first discovered by Henry Robert Richmond, Superintendent of the Taranaki Province (1865-1869), and then described in 1865 by James Hector (a Scottish geologist who was NZ’s leading scientist for many years, and after whom Hector’s dolphin was named) and William Skey (an analytical chemist). The details of their publication are as follows: “Taranakite, a new phosphatic mineral, Taranaki, presented by H. Richmond, Esq.” in Appendix A. Supplementary Report on Class 1. Reports of the Jurors, New Zealand Exhibition, pp. 423-425 (available online here). [The authoritative mindat.org mineral database entry on Taranakite mistakenly has “Expedition” instead of “Exhibition” in the title of this article.]

Hector and Skey wrote that chemical analysis showed this mineral to be “essentially a double hydrous phosphate of alumina and potash, part of the alumina being replaced by sesqui-oxide of iron” (pages 423-424). Such a mineral had not been reported before and the authors had named it “after the locality where it is found”. 

Te Ara The Encyclopedia of New Zealand states that Taranakite is formed by a chemical reaction between bird droppings (guano) and weathered volcanic rock. Technically, Taranakite is a “hydrated alkali iron-aluminium phosphate mineral” with the chemical formula (K,Na)3(Al,Fe3+)5(PO4)2(HPO4)6·18H2O. As wikivisually.com puts it, it forms from the reaction of clay minerals or aluminous rocks with solutions enriched in phosphate derived from bat or bird guano or, less commonly, from bones or other organic matter. It is most commonly found in humid, bat inhabited caves near the boundary of guano layers with the cave surface. It is also found in constantly wet coastal locations that have been occupied by bird colonies, such as the Sugar Loaf Islands off Taranaki where Richmond found it. 

James Hector (see photos below) had been born in Edinburgh in 1834. He graduated with a medical degree in 1856 and was then appointed doctor and geologist on the Palliser Expedition to Canada which undertook exploration for new railway routes. In 1858, while in the Canadian Rockies, his horse kicked him and he was thought to be dead. However, he revived. “Kicking Horse” Pass and River were named after this event. In 1862, he was employed to go to Dunedin in New Zealand to conduct a three-year geological survey of Otago, soon after the discovery of gold there. It was during this time that he first employed William Skey. In 1865 Hector was appointed to found the Geological Survey of New Zealand, and it was in that year that he and Skey published the discovery of Taranakite.

James Hector became widely consulted by the New Zealand government on scientific matters. He was responsible at various periods for many scientific institutions, including the Meteorological Department, the Colonial Observatory, the Wellington Time-ball Observatory and the Botanic Garden of Wellington, and for the custody of the standard weights and measures and the Patent Office library. In fact, for 40 years, he controlled virtually every aspect of state-funded science in the country. He was knighted in 1887. He retired in 1903 and died in 1907. An account of his life and work can be found in Te Ara The Encyclopedia of New Zealand.

William Skey (see photos below) was born in London in 1835 and worked in farming before coming to New Zealand with his brother in 1860. After a couple of years spent in the Otago goldfields, James Hector appointed him as laboratory assistant to the Geological Survey of Otago. In 1865, Skey moved with Hector to Wellington when the latter set up the NZ Geological Survey. He spent 35 years as chemical analyst with the Survey. His job entailed the provision of chemical analyses by which the economic potential of geological discoveries could be assessed. For example, in the article he wrote with Hector announcing the discovery of Taranakite, Skey wrote that if Taranakite “could be obtained in quantity at a reasonable expense, it would be valuable as a source of phosphoric acid for agricultural purposes” (page 424). As well as his chemical analyst work, Skey maintained a strong interest in farming, and had a small property in the Carterton area. His other major interest was poetry, writing especially parodies of Shakespeare and Milton which have been described as deliciously awful.

When Skey died in 1900, James Hector wrote in his obituary that Skey had become a world authority in many aspects of mineral chemistry and petrology (the study of rocks). This is a remarkable achievement because Skey had very little formal training, he worked extraordinarily hard for long hours and low pay, and his work was carried out essentially in isolation, in basic conditions with unsophisticated scientific instruments. He was involved in the discovery of two of New Zealand’s 13 minerals, Tarankite and Awaruite. An account of William Skey’s life and work can be found in Te Ara The Encyclopedia of New Zealand

Taranakite has now been found in a wide range of locations across the globe (see the photo below left for the localities map from Mindat). The photo of Taranakite second from left below is from Chrystalls Beach on the coast near Milton in Otago, New Zealand: “Coming from a rock-stack used by sea-birds, this cross-section of a rock, probably basalt, shows alteration to taranakite caused by the action of guano. The compact white layer at the top is the taranakite.” The photo second from right below is from Skipton Caves, Mt. Widderin, Victoria, Australia: “White chalky mass of Taranakite…on minor basalt matrix.” The photo on the far right below shows Taranakite resulting from the alteration of bat guano in the Sassyk-Unkur cave in Kyrgyzstan. Source of all four photos is mindat.org.

I have found that the best researched and most informative account of Taranakite to be the one on classicgems.net. It notes that “it is very soft…, lacks cleavage and is malleable and unctuous (having a greasy or soapy feel). Taranakite gems are extremely rare, very small and considered to be a gem collector’s oddity.”

What is Hydrogrossular’s Place Among the Thirteen Minerals First Described From New Zealand?

Thirteen minerals have been first described from New Zealand and accepted as valid by the International Mineralogical Association. Hydrogrossular is the fourth one to have been so discovered. In a previous Post, I said I would look at these minerals. Simon Nathan has provided a list of the 13 on the website of the Geoscience Society of New Zealand. There are more informative comments by Nathan on them in Te Ara The Encyclopedia of New Zealand. Two very useful if more technical sources are Mindat.org, a non-commercial online mineralogical database (the world’s largest), and rruff.info, an integrated database of the chemistry, crystallography, x-ray and other analytical data about minerals. Rruff.info also includes online versions of important publications on different minerals.

A mineral is a naturally occurring inorganic solid, with a definite chemical composition, and an ordered atomic arrangement. Often the best way for a mineral to form is through the cooling of very hot water or other fluid which contains it in solution. A rock is made up of one or more minerals, most often more than one. In a rock, mineral grains are fused, cemented or bound together. For example, granite is a rock primarily composed of three minerals – quartz, mica and feldspar. The crystals of these three minerals interlocked during the cooling of molten magma. The quartz is grey and glassy, the feldspar is light, often in prismatic crystals, and the mica is glittery, being dark or silvery in colour. 

The following are the 13 New Zealand-origin minerals in the order in which they were discovered:

1) “Taranakite” (above left) is a fine-grained cream-coloured phosphate first described in 1865 by James Hector (NZ’s leading scientist at the time) and William Skey (an analytical chemist). It was named after the Province of Taranaki as it was first found on small islands near New Plymouth in that Province.

2) “Awaruite” (above middle), a natural nickel-iron alloy, was first described in 1885 by William Skey (mentioned in #1 above). It had been obtained from gold miners south of Haast on the West Coast of the South Island, around the Gorge River, and was named after nearby Awarua/Big Bay.

3) “Tuhualite” (above right), a violet crystal that is unique to New Zealand, was first identified by geologist Patrick Marshall in 1932. He had found it on Tuhua/Mayor Island in the Bay of Plenty, its only source. 

4) “Hydrogrossular” (above left) is a calcium-rich garnet that was first described by Colin Hutton, a geologist and later professor of mineralogy, in 1943. He analysed samples of the rock from the Nelson area. The presence of water and thus hydroxide in its chemical make-up led to its naming. (See previous Post.)

5) “Huttonite” (above middle) is a radioactive cream–coloured crystal, first discovered in beach sands from the West Coast by Colin Hutton (see #4 above) who sent it to Adolf Pabst, an American mineralogist, to analyse. It was first described in publication in 1951 by Pabst who named it in honour of Hutton.

6) “Wairakite” (above right) is a colourless to white crystal found in geothermal environments. It was discovered and named in 1955 by Alfred Steiner, a pioneer geothermal scientist. He had found it while examining hydrothermally altered drill cores at Wairākei in the course of exploration for geothermal steam.

7) “Wairauite” (above left) was announced in 1964 by G.A. Challis and J.V.P. Long who worked in the  Department of Mineralogy and Petrology at the University of Cambridge. It is a natural cobalt-iron alloy and was discovered by electron micro-probe analysis of Awaruite (#2 above). Wairauite occurs as microscopic, scattered grains in serpentinite, often alongside Awaruite, the grains rarely exceeding 5 microns (0.005 millimetres), so electron micro-probe is the only way to see it. It is named Wairauite as the grains initially analysed were found in the Red Hills serpentinites of the Wairau Valley in Marlborough. [Serpentinite is a rock composed of one or more serpentine group minerals, the name originating from the similarity of the texture of the rock to that of the skin of a snake.] [An electron micro-probe is an analytical tool used to non-destructively determine the chemical composition of small volumes of solid materials. It works similarly to a scanning electron microscope.] 

8) “Akatoreite” (above middle) is a fibrous yellow-orange to orange-brown mineral recognised by Peter Read and Tony Reay (geologists from Carleton University and the University of Otago respectively). It is a previously unknown manganese silicate mineral. They reported in their 1971 publication that the mineral was found in a manganese-rich patch of chert and carbonate on the South Otago coast, three kilometres south of the mouth of the Akatore Creek, about 12 kilometres east of Milton. 

9) “Motukoreaite” (above right) is a poorly cemented fine-grained calcareous rock that occurs on Browns Island/Motukorea in the Waitematā Harbour, Auckland. The rock was first noted in 1941 by John Bartrum, a Professor of Geology, who called it “beach limestone”. It was not officially described and named as Motukoreaite until 1977 in an article by  Kerry Rogers (University of Auckland),  James Chisholm (British Museum), R.J. Davis (British Museum) and Cam Nelson (University of Waikato). It occurs as a boxwork of tiny crystals, each about 3 microns (0.003 millimetres) across. The crystals are semi-transparent and are white, pale yellow, pale yellow-green, or colourless.

10) “Feruvite” (above far left) is a dark brownish-black iron-rich variety of tourmaline found in a coarse-grained granitic rock on Cuvier Island/Repanga. The island is located 23 kilometres south-east of Great Barrier Island, a similar distance to the north-east of Coromandel Peninsula. Philippa Black from the University of Auckland had noted the occurrence of a iron-rich tourmaline on Cuvier in 1971. She later provided specimens to Joel Grice and George Robinson of the National Museum of Natural Sciences, Ottawa, who found they contained this previously unknown mineral. Grice and Robinson published their discovery in 1989. The mineral is part of the uvite group, and as it is rich in iron (Fe), it was named Feruvite.

11) “Coombsite” (above second from left) consists of tiny brownish-yellow fibrous crystals. These were found in brown patchy aggregates from a small area of manganese-rich rock at Watsons Beach on the South Otago coast (only about 3.5 kilometres south of where Akatoreite is found). Two Japanese mineralogists, Teruhiko Sameshima and Yosuke Kawachi, discovered this new manganese mineral and described it in 1991. They named it in honour of Douglas Coombs, Professor of Geology at the University of Otago. Coombsite is very rare and has been found in only three localities worldwide, in New Zealand, Brazil and Romania.

12) “Ferroceladonite” (above second from right) and 13) “Ferroaluminoceladonite” (above far right) were discovered in the 1990s when crystals from the Hokonui hills, east of Gore, were analysed by electron micro-probe. Previously the crystals had been identified as celadonite, a well-known mica group mineral found in altered volcanic rocks. However, the micro-probe analysis revealed two new minerals, which were named Ferroceladonite and Ferroaluminoceladonite. The crystals are extremely small, only 1 to 2 microns thick. A publication authored by Gejing Li, Donald Peacor, Douglas Coombs and Yosukee Kawachi identified these two minerals in 1997. Ferroceladonite is clay-like, usually green, and includes fine coatings and powdery masses. It was named for its ferrous content and its relation to celadonite. Ferroaluminoceladonite was also reported to be usually green in colour, is described as earthy, and its name reflects the significance of the presence of aluminium.

Future Posts will look at these 13 minerals and their discovery in more detail. The first is Taranakite: The Story of the First Mineral Described From New Zealand. The second is Awaruite: The Story of the Second Mineral Described From New Zealand.