Cleavage

Other

Mineral

One

Colorless, yellow, brown, pink, blue in color; vitreous luster; elongated crystals with striated faces and pointed ends

Topaz

Al₂SiO₄(OH,F)₂

Bluish green, yellow, white, pink in color; elongated, six-sided crystal prisms with flat ends

Beryl

Be₃Al₂(Si₆O₁₈)

Light blue to greenish blue in color; vitreous luster; blade-shaped crystals

Kyanite

Al₂SiO₅

White, pale green, brown in color; long slender crystals often in groups of parallel crystals

Sillimanite

Al₂SiO₅

Two

Salmon-pink, white, gray, green in color; vitreous luster; nearly right-angle or 90 degree cleavage

Potassium Feldspar

KAlSi₃O₈

White, dark gray or sometimes buff in color; vitreous luster; nearly right-angle or 90 degree cleavage; straight or parallel striations may show

Plagioclase Feldspar

NaAlSi₃O₈ to CaAl₂Si₂O₈

Pistachio green, yellowish green in color; elongated crystals or finely crystalline masses

Epidote

Hydrous Ca-Fe-Al silicate

Black; vitreous luster; possible faint green-gray streak; two perfect cleavages at 124 degrees and 56 degrees; stepped cleavage faces

Hornblend

Hydrous Na-Ca-Mg-Fe-Al silicate

Black, dark green in color; vitreous to dull in luster; two imperfect cleavages meeting at nearly 90 degrees (see also table MT6)

Augite

Ca-Mg-Fe silicate