Cyanotrichite , Malachite Locality: Maid of Sunshine Mine, Turquoise District (Courtland-Gleeson District), Dragoon Mts, Cochise County , Arizona , USA ( Locality at mindat.org ) Size: 6.2 x 5.2 x 4.4 cm. Cyanotrichite is an uncommon copper sulfate found in the oxidation zone of copper ore bodies. This rich and very colorful layered specimen has tiny, acicular, radiating, powder-blue to royal-blue cyanotrichite needles with contrasting green malachite in gossan matrix. This fine, old piece from the Maid of Sunshine Mine of Arizona. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Cyanotrichite
A hydrous copper-aluminium sulfate forming velvety sky-blue radial tufts of hair-fine needles — also known as lettsomite.
Intro adapted from Wikipedia (CC BY-SA).
Cyanotrichite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Cu₄Al₂(SO₄)(OH)₁₂(H₂O)₂.
It is a member of the Cyanotrichite structural group.
Key properties: specific gravity 2.74–2.95; Pale blue streak; Silky luster; optically biaxial.
IMA symbol Cya, IMA status: approved, named in 1839.
Occurs as an uncommon secondary mineral in the oxidized portions of copper sulfide deposits.
It is found associated with Brochantite, spangolite, chalcophyllite, olivenite, tyrolite, parnauite, azurite, malachite.
Its name comes from the Greek for blue and hair, in allusion to the typical color and habit.