Ingodite
Chemical formula: Bi₂TeS
Ingodite is a rare bismuth tellurosulfide, forming small, hexagonal flakes with a metallic luster, found in quartz veins.
Properties
- Mohs hardness
- 2.5
- Color
- Silver-white
- Luster
- Metallic
- Streak
- Grayish black
- Density
- 0
- Cleavage
- Perfect on {0001}
- Fracture
- Micaceous
- Transparency
- Opaque
- Crystal system
- Trigonal
Diagnostic features
## Identification Identifying Ingodite with the naked eye is practically impossible. Identification requires advanced laboratory methods, such as chemical composition analysis (EDS/WDS) using an electron microscope and X-ray diffraction (XRD) analysis. Under a reflected light microscope (ore microscope), it exhibits a creamy white color with a pinkish hue and strong anisotropy. ## Distinguishing from Similar Minerals Ingodite can be confused with other bismuth sulfides, tellurides, and sulfosalts, such as bismuthinite, tellurobismuthite, joseite-A, or joseite-B. Distinguishing it from these is possible almost exclusively based on precise chemical analysis, which will show the simultaneous presence of bismuth, tellurium, and sulfur in specific proportions. ## Crystal Forms Ingodite forms very small, thin, hexagonal flakes and plates. It occurs as single, dispersed crystals or small aggregates intergrown in the host rock, most often in quartz.
Geological environment
## Genesis Ingodite is a hydrothermal mineral. It forms in medium-temperature quartz-gold veins. Its presence is associated with mineralization processes in which solutions rich in bismuth, tellurium, and sulfur crystallize in rock fissures. ## Mineral Associations This mineral co-occurs with other ore minerals. It is most often accompanied by: native gold, native bismuth, bismuthinite, tellurobismuthite, joseite-A, joseite-B, as well as pyrite and chalcopyrite. The gangue mineral (host rock) is usually quartz. ## Localities Ingodite is an extremely rare mineral, confirmed in only a few localities worldwide. The most important of these are: - **Russia:** Zolotogorskoe gold deposit, Transbaikal region - type locality. - **China:** Sidaogou gold deposit in Heilongjiang Province. - **Czech Republic:** Jílové u Prahy gold mine in the Central Bohemian Region.
Rarity
Extremely rare
For collectors
## Quality Criteria The quality of Ingodite specimens is primarily assessed based on confirmation of its identity through analysis. Since the crystals are microscopic, any specimen on which well-formed flakes with a characteristic color can be observed (under high magnification) is considered valuable. Associations with clearly visible native gold are particularly prized. ## Popular Localities The vast majority of collector material, though still extremely rare, comes from the type locality in Russia (Zolotogorskoe deposit). Specimens from other confirmed localities are practically unavailable on the market.
Care and storage
## Cleaning Ingodite specimens should generally not be cleaned mechanically or chemically due to their delicacy and microscopic nature. If cleaning is absolutely necessary, compressed air (from a safe distance) can be used to remove dust. Avoid contact with water and all liquids. ## What to Avoid Avoid contact with chemicals, acids, and bases, which can damage the mineral. Ingodite is soft and easily scratched. It should be protected from ultrasound and sudden temperature changes. Prolonged exposure to humid air can lead to slow oxidation. ## Storage Ingodite specimens, as microminerals, are best stored in specialized "micromount" boxes, which protect them from dust, mechanical damage, and humidity changes. Avoid direct exposure to sunlight.