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Molybdate

Sidwillite

MoO₃·2H₂O
Hardness2.5
Crystal systemMonoclinic
ClassMolybdate
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Sidwillite specimen

Cluster of dark green sidwillite crystals. Field of view 3 mm. From: Freedom No. 2 Mine, Marysvale Mining District, Piute County, Utah, USA. Specimen and photo Leon Hupperichs. — Photo: Leon Hupperichs · CC BY-SA 3.0

Sidwillite

Sidwillite is an IMA-recognized mineral species in the molybdate class, with the chemical formula MoO₃·2H₂O.

It crystallizes in the monoclinic crystal system (space group P2_1/n).

Key properties: Mohs hardness 2.5; specific gravity 3.12; Pale yellow streak; Resinous to adamantine luster; optically biaxial.

IMA symbol Sdw, IMA status: approved, named in 1983.

An oxidation product of jordisite in a quartz vein.

It is found associated with Jordisite, quartz.

The mineral was named to honor Dr. Sidney Arthur Williams (1933–), American mineralogist and petrologist of Douglas, Arizona, USA.

Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet. Browse more S minerals or help write this entry.