Hidalgoite Locality: Gold Hill Mine (Western Utah Mine), Gold Hill, Gold Hill District (Clifton District), Deep Creek Mts, Tooele Co., Utah, USA Size: 6.4 x 5.2 x 2.7 cm Hidalgoite is a rare lead aluminum arsenate-sulfate and this very rich and uncommon small cabinet is from the Gold Hill Mine of Utah. All sides of the vuggy matrix wedge are richly covered with pretty pastel-green hidalgoite, either as massive crusts, striking, swirl-like patterns or tiny botryoids of hidalgoite. The crest holds a major, hidden surprise of a 2.5 cm vug lined with larger, greenish-yellow hidalgoite botryoids. Outstanding and rich older material from the Ed Bancroft Collection and accompanied by a Ward’s label. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Hidalgoite
A rare lead-aluminium arsenate-sulfate of the alunite family, named for Mexico's Zimapán district in Hidalgo.
Intro adapted from Wikipedia (CC BY-SA).
Hidalgoite is an IMA-recognized mineral species in the arsenate class, with the chemical formula PbAl₃(SO₄)(AsO₄)(OH)₆.
It crystallizes in the hexagonal crystal system. It is a member of the Alunite-beudantite structural group.
Key properties: Mohs hardness 4.5; specific gravity 3.71–3.96; White streak; Dull in aggregates luster; optically uniaxial.
IMA symbol Hid, IMA status: approved, named in 1953.
A rare secondary mineral of the oxide zone of polymetallic sulfide deposits.
It is found associated with Beudantite, tourmaline, “limonite” (San Pascual mine, Mexico); mansfieldite, carbonate-cyanotrichite (Cap Garonne mine, France).
The name refers to Hidalgo, the state in Mexico that produced the first specimens.