Lapis Lazuli | Gemopedia

Discover the mystical allure of rich, royal blue and sparkling golden specks found in lapis lazuli. Very few gems have such a long and storied history as lapis lazuli. Along with carnelian, it is the oldest known gemstones to be appreciated and worn as adornment. When lapis lazuli was first introduced to Europe, it was called ultramarine, meaning "beyond the sea." The gem was ground to a powder for use as early eye shadow, and as pigment for early oil paints. Today, this rich blue gem still retains the allure that first captivated humans thousands of years ago.
Alternate
Names
Lapis
Colors
Medium To Dark, Slightly Greenish Blue To Violetish Blue

Lapis Lazuli Classification

Common Name

Lapis Lazuli

Species

NA

Variety

Colors

Medium To Dark, Slightly Greenish Blue To Violetish Blue

Alternate Names

Lapis

Gemstone Groups

Key Separations

Apperance, RI, magnification and possibly fluorescence

Comments

Some areas of the stone might have a RI of 1.67 due to calcite inclusions. Lapis lazuli is a mixture of lazurite, calcite and pyrite.

Lapis Lazuli Optical Properties

Transparency

Semitranslucent - Opaque

Refractive Index

1.5

Birefringence

Optic Character

NA

Optic Sign

NA

Polariscope Reaction

Aggregate (AGG)

Fluorescence

SWUV: weak to moderate green to yellowish green
LWUV: Inert

CCF Reaction

dull reddish brown

Pleochroism

None

Dispersion

Strength: none

Comments

Lapis Lazuli Chemistry & Crystallography

Chemical Name

sodium calcium aluminum silicate

Chemical Formula

(Na,Ca)8[(SiO4,S,Cl)2I(AlSi)4]6

Synthesis

Crystal System

NA

Classification

Silicate

Nature

Natural

Crystallinity

Polycrystalline

Comments

Lapis Lazuli Characteristic Physical Properties

Hardness

5-6

Streak

White To Light Blue

Specific Gravity

2.25-3 Typical:2.75

Toughness

Fair

Inclusions

Lapis lazuli commonly contains pyrite and white calcite. The pyrite inclusions in natural stones are randomly scattered throughout the stone and have irregular outlines that are surrounded by darker blue rings.

Luster

Vitreous

Stability

Fracture

Granular, Uneven

Cleavage

None

Comments

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