Olgafrankite

Chemical formula: Ni₃Ge

Olgafrankite is an extremely rare, naturally occurring nickel-germanium alloy, forming silvery, metallic grains.

## Characteristics Olgafrankite is a natural alloy (intermetallic compound) of nickel and germanium. It occurs as very small, irregular grains, typically not exceeding 0.1 mm in size. Its appearance is typically metallic, with a silvery color and strong luster. Due to its extreme rarity and microscopic size, it is a mineral known primarily from scientific research. ## Physical Properties This mineral is characterized by a hardness of 5.5 on the Mohs scale, placing it on par with apatite or glass. It has a high, metallic luster and is opaque. Its calculated density is very high, at 8.93 g/cm³, which is comparable to the density of pure nickel. ## Colors and Varieties Olgafrankite has a uniform, silvery color. No color varieties or commercial forms are known. ## History and Name The mineral's name honors Olga Evgenievna Frank-Kameneckaya (born 1945), a Russian crystallographer and mineralogist from Saint Petersburg State University. It was approved as a new mineral species by the International Mineralogical Association (IMA) in 2022. The type locality, the first documented occurrence, is the Dzheltul massif in Siberia, Russia. ## Uses Olgafrankite has no industrial or commercial applications. Its significance is purely scientific and as a collector's item, as an extremely rare natural intermetallic compound.

Properties

Mohs hardness
5.5-0
Luster
Metallic
Streak
silver
Density
8.927
Fracture
Irregular/Uneven
Transparency
Opaque
Crystal system
Isometric

Diagnostic features

## Identification Identification of olgafrankite is impossible without advanced analytical techniques. It requires the use of a scanning electron microscope (SEM) with chemical composition analysis (EDS/WDS) to confirm the presence of only nickel and germanium in the correct proportions. Its silvery, metallic appearance in the host rock is an indicative feature but insufficient for identification. ## Distinguishing from Similar Minerals It can be confused with other fine-grained, metallic minerals occurring in similar environments, such as other natural alloys (e.g., awaruite), sulfides, or platinum-group minerals. Definitive distinction is possible only through chemical analysis. ## Crystal Forms Olgafrankite forms very small, anhedral (irregular) grains and aggregates, typically with an irregular shape. Well-formed crystals have not been observed.

Geological environment

## Genesis Olgafrankite forms in ultramafic igneous rocks, particularly picrites. Its crystallization occurs under conditions of high temperature and low sulfur activity, which allows for the formation of intermetallic compounds instead of sulfides. ## Mineral Associations This mineral co-occurs with other rare minerals at its type locality. It is mainly associated with graphite, awaruite (Ni₃Fe), cohenite ((Fe,Ni,Co)₃C), chalcopyrite, pentlandite, heazlewoodite, as well as other germanium and nickel compounds. ## Localities The only confirmed occurrence of olgafrankite in the world is its type locality - the Dzheltul (Dzhaltul) massif on the Kureika River, in Krasnoyarsk Krai, Siberia, Russia.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of an olgafrankite specimen depends solely on the confirmation of its presence through analysis and on the abundance and size of the grains in the host rock. As it is a microscopic mineral, specimens are primarily valued by specialized scientific institutions and collectors of "systematic" or "micromount" minerals. Visual aesthetics are of secondary importance. ## Popular Localities The only source of specimens is the type locality in Russia. Availability on the collector's market is practically zero.

Care and storage

## Cleaning Due to the microscopic size of the grains and their occurrence within the host rock, cleaning individual specimens is practically impossible and not recommended. The host rock specimen can be gently dusted with a soft brush. ## What to Avoid Avoid contact with strong acids and other aggressive chemicals that could react with the metallic alloy. Also, protect the specimen from moisture to prevent potential oxidation. ## Storage Specimens containing olgafrankite should be stored in stable, dry conditions, preferably in a sealed "micromount" box, to protect them from dust and mechanical damage.

External references

Sources

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