Mineraloids

7 minerals in this group.

Opal

SiO2·nH2O

H: 6SG: 2.1Amorphous

Obsidian

Volcanic glass (SiO2 rich)

H: 5.5SG: 2.4Amorphous

Moldavite

SiO2 (+ Al2O3, etc.)

H: 5.5SG: 2.4Amorphous

Amber

C10H16O + succinic acid

H: 2.5SG: 1.1Amorphous

Jet

Carbon (lignite)

H: 3SG: 1.3Amorphous

Tektite

SiO2 rich natural glass

H: 5.5SG: 2.4Amorphous

Pumice

Volcanic glass (SiO2 rich)

H: 6SG: 0.5Amorphous