MT2: Minerals with Nonmetallic Luster

Reference
Tables

MT2

Hardness >5.5 Streak that is white or appears white like No cleavage
Cleavage	Other	Mineral
None	Brown, pink, blue or gray in color; six-sided prismatic crystals; ruby (red color) and sapphire (blue) are gem varieties of this mineral	Corundum Al₂O₃
	Black, pink, blue, green, brown in color; vitreous luster; thin crystals with triangular cross sections and striated faces	Tourmaline Complex hydrous silicate
	Reddish brown, yellowish tan in color; vitreous to resinous luster; twelve-sided crystals; broken surfaces may resemble cleavages	Garnet Ca-Mg-Fe-Al silicate
	Red-brown, brownish-black in color; vitreous, resinous or dull luster; prismatic and X or cross-shaped crystals	Staurolite Hydrous Fe-Al silicate
	Varied appearance with larger crystalline varieties exhibiting a clear, milky, white, purple, smokey or pink color; vitreous luster; Small crystalline varieties exhibiting gray, black, brown or multicolor banded appearance; vitreous luster	Quartz SiO₂
	Olive-green to yellow-green in color; vitreous to dull luster	Olivine (Mg,Fe)SiO₄
	Colorless, white, or pale shades of yellow, green, red or blue in color; vitreous to resinous luster	Opal SiO₂ nH₂O