Molybdite , Molybdenite Locality: Questa Molybdenum Mine (Moly Mine; R and S Mine), Questa , Taos County , New Mexico , USA ( Locality at mindat.org ) Size: 11.0 x 6.7 x 4.1 cm. Molybdite is an uncommon molybdenum oxide and this cabinet specimen is a rare and rich specimen from New Mexico out of the Mullane Collection. Pastel-yellow molybdite richly covers the metallic-gray molybdenite and quartz on both sides of this old-time piece from the Questa Molybdenum Mine in Taos County. Accompanied by an old and faded handwritten label. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Molybdite
Natural molybdenum trioxide — yellow-to-green orthorhombic needles formed where molybdenite oxidizes.
Intro adapted from Wikipedia (CC BY-SA).
Molybdite is an IMA-recognized mineral species in the molybdate class, with the chemical formula MoO₃.
It crystallizes in the orthorhombic crystal system (space group Pbnm).
Key properties: Mohs hardness 3.5; specific gravity 4.5; Adamantine luster; optically biaxial.
IMA symbol Myb, IMA status: approved, named in 1907.
Found in cavities and coating molybdenite in a weathered quartz vein near its contact with topaz-quartz greisen.
It is found associated with Molybdenite, betpakdalite, quartz.
As an oxide of molybdenum.