Dumortierite | Gemopedia

A mineral that often forms as an inclusion in quartz, dumortierite is a mineral that is often fashioned as cabochons or beads for jewelry. While prized for its deep violet to blue colors, it may also be found in shades of pink, gray and brown. Named for French paleontologist Eugne Dumortier, dumortierite is an exotic gem that is durable, untreated and rare.
Colors
Dark Blue, Violet Blue, Greenish Blue, Green, Red-Brown, Colorless

Dumortierite Classification

Common Name

Dumortierite

Species

Dumortierite

Variety

Colors

Dark Blue, Violet Blue, Greenish Blue, Green, Red-Brown, Colorless

Alternate Names

Gemstone Groups

Key Separations

RI and SG

Comments

Dumortierite is often found as inclusions in quartz.

Dumortierite Optical Properties

Transparency

Translucent - Opaque

Refractive Index

1.678-1.689

Birefringence

0.015-0.037

Optic Character

Biaxial

Optic Sign

Negative

Polariscope Reaction

Doubly Refractive (DR)

Fluorescence

SWUV: Moderate bluish white
LWUV: Inert to yellowish white or red

CCF Reaction

Pleochroism

Unobservable

Dispersion

Strength: none

Comments

Dumortierite Chemistry & Crystallography

Chemical Name

Chemical Formula

Al7(BO3)(SiO4)3O3

Synthesis

Crystal System

Orthorhombic

Classification

Silicate

Nature

Natural

Crystallinity

Crystalline to Aggregate

Comments

Dumortierite Characteristic Physical Properties

Hardness

7-8.5

Streak

White

Specific Gravity

3.26-3.41

Toughness

Inclusions

Dumortierite is most common in its fibrous or granular structured variety.

Luster

Vitreous

Stability

Fracture

Conchoidal

Cleavage

Good, in one direction, Poor, in one direction

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