Star garnet

About it

Almandine with fine needle inclusions that show a four- or six-rayed star when cut as a cabochon. Idaho's state gem, dug from gravels near Emerald Creek; also found in India.

Type

Variety

Group

Almandine variety (garnet)

Formula

Fe3Al2(SiO4)3

Hardness (Mohs)

7–7.5

Specific gravity

3.93–4.3

Streak

white

Lustre

vitreous (glassy)

Crystal system

Isometric (cubic)

Colours

dark purplish red, brownish red, nearly black

Transparency

translucent, opaque

Cleavage and fracture

none; conchoidal to uneven fracture

Typical values: real specimens vary. For more, see mindat.org.