Topaz Natural Size Teardrop

Topaz

General

Category

Minerals nesosilicatos

Class

9.AF.35 (Strunz)

Chemical formula

Al₂SiO₄(OH, F)₂

Physical properties

Color

Pale blue, yellowish brown, colorless, red, yellow

Stripe

White

Luster

Vitreous

Transparency

Transparent to translucent

Crystal system

Orthorhombic

Habit lens

Prisms shorts, prisms, long, massive, granular, columnar

Exfoliation

perfect

Fracture

concoidal

Hardness

8

Density

3,55 g/cm³

Index of refraction

na = 1.606–1.629 nß = 1.609–1.631

ny = 1.616–1,638 in

Birefringence

δ = 0.010

Pleochroism

Weak in thick sections

Optical properties

Biaxial (+)

Fluorescence

Yes