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).
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.
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