Molybdite

Molybdite

Molybdite on molybdenite from the Questa Molybdenum Mine (size: 11.0 x 6.7 x 4.1 cm)
General
Category Mineral
Formula
(repeating unit)
MoO3
Strunz classification 4.EA.10
Crystal system Orthorhombic
Space group Orthorhombic dipyramidal
H-M symbol: (2/m 2/m 2/m)
Space group: Pbnm
Unit cell a = 3.96 Å, b = 13.85 Å, c = 3.69 Å; Z=4
Identification
Color Light greenish yellow to nearly colorless
Crystal habit Flattened needles or thin plates may occur in aggregates
Cleavage Perfect on {100}, district on {001}
Tenacity Flexible
Mohs scale hardness 3 - 4
Luster Adamantine
Streak White
Diaphaneity Transparent
Specific gravity 4.72
Optical properties Biaxial (+)
Birefringence High
2V angle Large
References [1][2][3]

Molybdite is the naturally occurring mineral form of molybdenum trioxide MoO3. It occurs as yellow to greenish needles and crystallizes in the orthorhombic crystal system.

Discovery and occurrence

Molybdite was first described in 1854 for and occurrence in quartz veins in the Knöttel area of Krupka, Krušné Hory Mountains in the Ústí Region of Bohemia, Czech Republic.[2] It occurs in vein cavities and as coatings in molybdenite ore veins and quartz topaz greisens. Associated minerals include molybdenite, betpakdalite and quartz.[1] The similar mineral ferrimolybdite is often misidentified as molybdite.[1]

References

This article is issued from Wikipedia - version of the 4/8/2013. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.