Thortveitite

Thortveitite is a rare mineral consisting of scandium yttrium silicate (Sc,Y)₂Si₂O₇. It is the most widespread scandium mineral,^[2] but natural thortveitite is not widely exploited as a source of scandium metal. Most scandium is derived from mine tailings, which can include thortveitite.^[3] Thortveitite mining in the United States ceased in 1969.^[4]

Thortveitite
Thortveitite
General
Category	Minerals
Formula	(Sc,Y)2Si2O7
IMA symbol	Tvt[1]
Strunz classification	9.BC.05
Crystal system	Monoclinic
Crystal class	Prismatic (2/m) (same H-M symbol)
Space group	C2/m
Identification
Mohs scale hardness	5–6
Luster	vitreous
Streak	gray
Specific gravity	3.3–3.8

Occurrence is in granitic pegmatites. It was named after Olaus Thortveit, a Norwegian engineer. It is grayish-green, black or gray in color.^[5][6][7][8]

A transparent gem quality example was found in 2004, and reported in The Journal of Gemmology.^[9]

See also

• List of minerals
• List of minerals named after people