Argutite

Argutite, formula- (GeO₂) is a rare germanium oxide mineral. It is a member of the rutile group.

It was first described as an occurrence in the Argut deposit, central Pyrenees, Haute-Garonne, France in 1983. The type locality is within a zinc ore deposit within lower Paleozoic sedimentary rocks that have undergone metamorphism. Associated minerals include sphalerite, cassiterite, siderite, and briartite.

General Information

Category: Oxide mineral
Formula: GeO₂
Crystal system: Tetragonal
Space group: Tetragonal
Transparency: Translucent.
Density: 6.28 g/cm³ (Calculated).

Properties

Color: Grayish black, light gray in reflected light
Crystal habit: Subhedral crystals, as inclusions in sphalerite
Mohs scale hardness: 6-7
Luster: Vitreous – adamantine
Diaphaneity: Transparent to opaque
Specific gravity: 6.28 calculated.

Mutual solubilities in crystalline phases in the system SiO₂–GeO₂ have been investigated up to 10 GPa pressure and 1500°C temperature, using a bulk composition of 50 mol% GeO₂. The solid solution of up to 40 mol% GeO₂ into the mineral quartz has been confirmed as well as the solubility of Si into GeO₂ rutile (argutite) and Ge into SiO₂ rutile (stishovite) phases and limited Ge into coesite. The extensive solubility of SiO₂ in GeO₂ is found in argutite at 1200°C, increasing strongly with pressure and reaching a maximum of 25.2 mol% SiO2 in GeO₂ at 9 GPa.

In short:

Mineral Group: Rutile group.
Occurrence: In a zinc deposit formed in metamorphosed lower Paleozoic sediments.
Association: Sphalerite, cassiterite, siderite, briartite.
Distribution: From the Argut deposit, the central Pyrenees, Haute-Garonne, France.
Name: For the occurrence in the Argut deposit, France.

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