Seraphinite

Seraphinite
Seraphinite specimen
General
Category	Phyllosilicate minerals
Group	Chlorite group
Formula	(Mg, Fe3+Al(Si3Al)O10(OH)8
Crystal system	Monoclinic
Identification
Color	green, white, colourless
Mohs scale hardness	2–2.5
Luster	Pearly, dull, greasy
Streak	light green
Diaphaneity	transparent, translucent to opaque
Specific gravity	2.600–3.000
Optical properties	Biaxial (–)
Refractive index	1.571–1.597
Birefringence	0.005–0.011
Ultraviolet fluorescence	inert

Seraphinite is a trade name for a particular form of clinochlore, a member of the chlorite group.

Seraphinite apparently acquired its name due to its resemblance to feathers due to its chatoyancy. Seraphinite is named after the biblical seraphs or seraphim angels. With some specimens the resemblance is quite strong, with shorter down-like feathery growths leading into longer "flight feathers"; the resemblance even spurs fanciful marketing phrases like "silver plume seraphinite." Seraphinite is generally dark green to gray in color, has chatoyancy, and has hardness between 2 and 4 on the Mohs scale of mineral hardness.

Seraphinite is mined in a limited area of eastern Siberia in Russia. Russian mineralogist Nikolay Koksharov (1818-1892 or 1893) is often credited with its discovery. It occurs in the Korshunovskoye iron skarn deposit in the Irkutskaya Oblast of Eastern Siberia.