Dienerite

Chemical formula: Ni₃As

Dienerite is an extremely rare nickel arsenide, historically described in one location worldwide, whose existence as a distinct mineral is questioned.

## Characteristics Dienerite is a nickel arsenide, described as a mineral with a metallic appearance and a white-gray color. Its occurrence has only been reported in the form of small, rounded grains in placer deposits. Due to the lack of subsequent findings and the incompleteness of the original description from 1926, its status as a valid mineral species is currently discredited by the International Mineralogical Association (IMA). ## Physical properties It was described as an opaque mineral with a metallic luster. Density and hardness have not been reliably measured. The original description suggested it was brittle. ## Colors and varieties The reported color is white with a gray tint. No varieties are known. ## History and name The mineral was described by Paul Ramdohr in 1926 based on material from the Josephine Creek placers in Oregon, USA. The name honors Karl Diener (1862-1928), a professor of paleontology at the University of Vienna. However, due to the inability to re-examine the type material and confirm its properties, dienerite was discredited as a mineral species in 1980.

Properties

Luster
Metallic
Density
0
Transparency
Opaque
Crystal system
Isometric

Diagnostic features

## Identification Identification of dienerite is practically impossible outside of advanced laboratory methods, such as chemical composition analysis (EDS) and X-ray diffraction (XRD). Any alleged findings require scientific verification. ## Distinguishing from similar minerals It can be confused with other metallic nickel arsenides, such as maucherite (Ni₁₁As₈) or niccolite (NiAs), from which differentiation is only possible based on precise structural and chemical analysis. ## Crystal forms Only rounded, irregular grains have been described. Crystalline forms are not known.

Geological environment

## Genesis The original material was found in concentrates from alluvial (placer) deposits. This suggests that it originated from weathered and eroded parent rock, likely ultramafic (serpentinite), where it could have formed under hydrothermal conditions. ## Mineral associations It was found in association with chromite, platinum, gold, awaruite, and other heavy, weathering-resistant minerals. ## Localities The only reported occurrence worldwide is the historical placer deposits along Josephine Creek in Josephine County, Oregon, USA. The mineral has never been confirmed from any other locality.

Rarity

Extremely rare

For collectors

## Quality criteria Since the existence of dienerite as a distinct mineral is questioned, and the type material is unavailable, it has no significance in the collector's market. Any confirmed material would have immense scientific, not commercial, value. Criteria such as color or form do not apply.

Care and storage

## Cleaning Due to its extreme rarity and questionable status, any specimens (if they exist) have purely scientific and historical value. They should not be cleaned mechanically or chemically without consultation with a research institution. ## What to avoid Contact with chemicals, moisture, and abrasion should be avoided, as it is an arsenide and may oxidize, and is likely brittle. ## Storage Store in stable conditions, in a sealed, padded display box, away from moisture and chemically reactive substances.

External references

Sources

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