Molybdite

Molybdite
Molybdite on molybdenite from the Questa Molybdenum Mine (size: 11.0 x 6.7 x 4.1 cm)
General
CategoryMinerals
FormulaMoO3
IMA symbolMyb
Strunz classification4.EA.10
Crystal systemOrthorhombic
Crystal classDipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space groupPbnm
Unit cella = 3.96 Å, b = 13.85 Å,
c = 3.69 Å; Z = 4
Identification
ColorLight greenish yellow to nearly colorless
Crystal habitFlattened needles or thin plates may occur in aggregates
CleavagePerfect on {100}, district on {001}
TenacityFlexible
Mohs scale hardness3 - 4
LusterAdamantine
StreakWhite
DiaphaneityTransparent
Specific gravity4.72
Optical propertiesBiaxial (+)
BirefringenceHigh
2V angleLarge
References

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.