Lazulite Gem Guide and Properties Chart

This mineral species can be opaque to crystalline transparent. The color of lazulite ranges from medium to dark greenish blue to violet blue and is often mottled with white. When fashioned into gems, finished stones typically weigh less than 5 carats. A separate mineral species, lazulite should not be confused with lazurite or azurite.

General Information

Classification
Optical Properties
Characteristic Physical Properties
Chemistry & Crystallography

Common Name

Lazulite

Species

Lazulite

Transparency

Transparent - Opaque

Dispersion

Strength: None

Refractive Index

1.604-1.663 Tolerance: (+0.005/-0.005)

Birefringence

0.031- 0.037

Optic Character

Biaxial

Optic Sign

Negative

Polariscope Reaction

Aggregate (AGG), Doubly Refractive (DR)

Fluorescence

SWUV: inert
LWUV: inert

Pleochroism

Trichroic, strong dark violetish blue, colorless, and light blue

Hardness

5.5-6

Streak

White

Specific Gravity

3.090-3.240 Typical:3.090

Toughness

Poor

Inclusions

Transparent material is highly included. Aggregate lazulite material will have a mottled appearance with white areas.

Luster

Vitreous

Stability

Brittle

Fracture

Splintery, Uneven

Cleavage

Good, in one direction, Poor, in one direction

Chemical Name

hydrous magnesium iron aluminum phosphate

Chemical Formula

MgAl₂(PO₄)₂(OH)₂

Crystal System

Monoclinic

Chemistry Classification

Phosphate

Lazulite Colors

Yellow
Blue
Green
Black
Brown

Alternate Names

Bluespar

Countries of Origin

Myanmar; Afghanistan; Russian Federation; Czechia; United States of America; Madagascar; United Kingdom of Great Britain and Northern Ireland; Portugal; Austria; Sweden; Pakistan; Morocco; Unknown; China; Ireland; Brazil; Slovakia; Bulgaria; Chile; France; Argentina; Hungary; Japan; Rwanda; Switzerland; Bolivia (Plurinational State of); India; Spain; Canada; Norway; Namibia; Finland; Italy; Zimbabwe; Antarctica; Australia; Peru; Germany

History

Gets its name from the German word "lazurstein" which means blue stone.

Care

Lazulite is brittle so please handle with care. It is slowly soluble in acid in hot acid.