Formula: BeAl2O4
Origin of name: From Greek for golden and from beryl
Crystal system: Orthorhombic
Crystal class: 2/m 2/m 2/m
Twinning: Common on {130}, contact, penetration, or cyclic (sixlings)
Unit cell: a = 5.488 Ǻ, b = 9.423 Ǻ, c = 4.433 Ǻ
Colour: Yellowish green, yellow, grey, brown, blue-green
Diaphaneity:
Luster: Vitreous
Habit: Crystals thin to thick tabular or short prismatic; granular massive
Hardness: 8.5
Specific gravity: 3.75
Cleavage: 3; {110} distinct, {010} imperfect, {001} indistinct
Tenacity: Conchoidal to uneven; brittle
Streak:
Synonyms/varieties: Alexandrite (colour-change var.), cymophane (opalescent var.)
Comments:
| Back to Alphabetical list | Colour photos | Thin sections | SEM images | TEM images | vibrational spectra description | IR spectra | Raman spectra | N-IR spectra | F-IR spectra | IES spectra |