Altaite: Identification and Occurrence

Altaite, or lead telluride, is a yellowish white mineral with an isometric crystal structure. It is a mineral consisting of lead telluride PbTe tin-white when untarnished and usually occurring massive with cubic cleavage. It was named after the locality it was found in – Altai Mountains, Kazakhstan. It belongs to the Galena group. It is not Radioactive.

Altaite is in the Galena group of minerals as it shares many of properties of Galena. Altaite has an unusually high density for a light-colored mineral. Altaite and other rare tellurides are classified in the sulfide mineral class (Dana classification). It is also associated with gold and silver and several gold and silver sulfides and tellurides such as nagyagite, sylvanite, calaverite, and hessite.

General Information:

  • Category: Telluride mineral
  • Formula: PbTe
  • Crystal system: Isometric
  • Crystal class: Hexoctahedral
  • Tenacity: Sectile.

Identification

Altaite can be identified in the field by its color variations, such as tin-white, yellowish-tin-white, and bronze-yellow. This mineral has a metallic luster, with a black streak. The fracture of this mineral is brittle, with euhedral crystals. The density of altaite is 8.1 to 8.2 g/cm3, with a hardness of 2.5 – approximate to a fingernail.

  • Formula mass: 334.8 g/mol
  • Color: tin white to yellowish white; tarnishing to bronze yellow
  • Crystal habit: include cubic and octahedral crystals, but much more commonly found in massive and granular forms
  • Cleavage: perfect in three directions forming cubes
  • Fracture: Uneven
  • Mohs scale: hardness 2.5 – 3.
  • Luster: metallic
  • Streak: Black
  • Specific gravity: 8.2 – 8.3

Occurrence

Altaite occurs in hydrothermal vein Au–Te-bearing deposits. It was discovered in 1845 in the Altai Mountains. Besides these mountains altaite can also be found in Zyryanovsk, Kazakhstan; the Ritchie Creek Deposit in Price County, Wisconsin; the Koch-Bulak gold deposit in Kazakhstan; Moctezuma, Mexico; and Coquimbo, Chile among other locations.

It is often associated with minerals such as gold, silver, antimony, tellurantimony, galena, pyrite, hessite, tellurium, nagyagite, tetrahedrite, petzite, sphalerite, chalcopyrite, sylvanite, calaverite, jamesonite, boulangerite, arsenopyrite, bournonite, pyrrhotite, siderite, cerussite, quartz, and aguilarite.

 

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