Beryl (Aquamarine and Emerald) Identification Sheet

The beryllium silicate behind emerald, aquamarine, and morganite: long hexagonal prisms, harder than quartz, in pegmatites.

Rock type: Igneous, Hydrothermal

For: Collectors, Lapidary Artists

Mohs hardness 7, 8 7.5–8

Streak White

Luster Vitreous, Resinous Vitreous to resinous

CleavageImperfect basal {0001}

Crystal habit Prismatic, Columnar, Tabular Hexagonal prisms, often columnar; rarely tabular

Beryl forms clean six-sided prisms, often flat-ended and strikingly long, in granite pegmatites and some schists. Green gem beryl is emerald, blue-green is aquamarine, pink is morganite, and golden is heliodor. Its hardness of 7.5–8 (it scratches quartz) and hexagonal cross-section separate it from apatite, which it otherwise mimics.

Common lookalikes

Apatite (much softer at 5 — the classic trap), quartz (softer, no flat prism faces of beryl's perfection), topaz (perfect cleavage).