Chlorastrolite | Gemopedia

Also known as "green starstone" or "Michigan greenstone," chlorastrolite is a green to bluish green stone only found in the upper peninsula of Michigan, USA. This gem exhibits varying degrees of chatoyancy and has a distinctive "turtleback" mosaic pattern throughout.
Alternate
Names
Green Star Stone, Turtleback Stone, Isle Royale Greenstone, Lake Superior Greenstone
Colors
green to bluish green

Chlorastrolite Classification

Common Name

Chlorastrolite

Species

Chlorastrolite

Variety

Colors

green to bluish green

Alternate Names

Green Star Stone, Turtleback Stone, Isle Royale Greenstone, Lake Superior Greenstone

Gemstone Groups

Key Separations

Appearance: radial fibrous structure

Comments

State gemstone of Michigan.

Chlorastrolite Optical Properties

Transparency

Semitranslucent - Opaque

Refractive Index

1.65-1.66
Tolerance:(+0.040/-0.040)

Birefringence

Optic Character

Optic Sign

Polariscope Reaction

Aggregate (AGG)

Fluorescence

SWUV: Inert
LWUV: Inert

CCF Reaction

Pleochroism

Unobservable

Dispersion

Comments

Chlorastrolite Chemistry & Crystallography

Chemical Name

hydrated calcium magnesium silicate hydroxide

Chemical Formula

Ca2MgAl2(SiO4)(Si2O7)(OH)2-H2O

Synthesis

Crystal System

Monoclinic

Classification

Nature

Natural

Crystallinity

Aggregate

Comments

Chlorastrolite Characteristic Physical Properties

Hardness

5-6

Streak

Green

Specific Gravity

3.1-3.5 Typical:3.2

Toughness

Fair

Inclusions

Chlorastrolite has a fibrous structure with light and dark green mosaic like patterns

Luster

Vitreous

Stability

Fracture

Splintery, Granular

Cleavage

None

Comments

JTV on Google+
0 Items
My Wish List
Close
Item
Description
Qty.
Price


Estimated Order Total:
0
Total Due Today:
0
Close
Item
Description
Qty.
Price


Page of 1