Sanguite

Sanguite is a halide mineral. It is named after the Latin word sanguis, meaning blood, due to its bright red colouration. It was approved as a valid species by the International Mineralogical Association in 2013.

Sanguite
General
Category	Halides
Formula	KCuCl₃
IMA symbol	Sgu
Crystal system	monoclinic
Crystal class	2/m
Space group	2/ m - prismatic
Unit cell	V = 481.38 ų
Identification
Color	bright red
Twinning	polysynthetic twinning has been observed.
Cleavage	Perfect
Fracture	staggered, step-like
Tenacity	fragile
Luster	Vitreous
Streak	reddish orange
Density	2.86(1) g/cm³ (measured); 2.88 g/cm³ (calculated)
Optical properties	biaxial
Refractive index	n α = 1.653(3) n β = 1.780(6) n γ = 1.900(8)
Birefringence	δ = 0.247
Pleochroism	strong
2V angle	Measured: 85° (5) Calculated: 82°
Dispersion	very strong
References	[1]

Characteristics

Sanguite is a chloride with the chemical formula KCuCl₃. It crystallizes in the monoclinic system and has a Mohs scale hardness of 3.

Formation and deposition

Sanguite was discovered in the Glavnaya Tenoritovaya fumarole on the Tolbachik volcano in Kamchatka Krai, Russia, the only place on Earth where it is known to form.^[1] There it forms in clusters or crusts as fine prismatic crystals up to 1 mm long and 0.2 mm thick.