Cyclosilicate, mineral. It was formed as the result of fusion and recrystallization of rocks above burning coal seams. It was subsequently found in nature in hornfels, and rapidly quenched volcanic rocks.

Properties

Chemical formula

Mg₂Al₃(AlSi₅O₁₈)

Group

Silicates

Crystal system

Hexagonal

Hardness (Mohs)

—

Color

—

Luster

—

Streak

—

Density

—

Cleavage

—

Fracture

—

Tenacity

—

Crystal habit

—

Transparency

—

Space group

P6/mcc

Fluorescence

—

Magnetism

—

Radioactivity

—

Refractive index

—

Optical character

—

Birefringence

—

Pleochroism

—

Strunz classification

9.CJ.05

Dana classification

61.1.1.3

IMA status

Grandfathered mineral (G)

IMA symbol

Ind

Locality

—

Type locality

—

Discovery year

—

Source: Wikidata