Tyrolite is a hydrous calcium copper arsenate carbonate mineral with the formula CaCu₅(AsO₄)₂CO₃(OH)₄⋅6H₂O. Tyrolite forms glassy, blue to green orthorhombic radial crystals and botryoidal masses. It has a Mohs hardness of 1.5–2.0 and a specific gravity of 3.1–3.2. It is translucent with refractive indices of nα = 1.694, nβ = 1.726, and nγ = 1.730.

Tyrolite
General
Category	Arsenate and carbonate minerals
Formula (repeating unit)	CaCu5(AsO4)2CO3(OH)4·6H2O
IMA symbol	Tyl[1]
Strunz classification	8.DM.10
Crystal system	Orthorhombic
Crystal class	Prismatic (2/m) (same H-M symbol)
Space group	P2/c (no. 13) or C2/c (no. 15)
Identification
Color	Blue to green
Crystal habit	Radial or botryoidal
Mohs scale hardness	1.5–2.0
Luster	Vitreous
Diaphaneity	Translucent
Specific gravity	3.1–3.2
Refractive index	nα = 1.694 nβ = 1.726 nγ = 1.730
References	[2]

It is a secondary mineral formed by the weathering of associated copper and arsenic minerals. It was first described in 1845 for an occurrence in Schwaz, Tyrol, Austria.