Danburite | Gemopedia

In 1839 American mineralogist Charles Upham Shephard discovered a clear, bright, colorless gemstone in Danbury, Connecticut, and named it danburite after the location. Unfortunately for danburite, it was discovered at a time when colored gemstones were heavily promoted and highly desired. This colorless find, therefore, didn't create much excitement at that time. Danburite, which belongs to a class of minerals known as silicates, remained relatively unknown for years, but is steadily growing in popularity today.
Colors
Colorless, Light Yellow To Brown, Light Pink

Danburite Classification

Common Name

Danburite

Species

Danburite

Variety

Colors

Colorless, Light Yellow To Brown, Light Pink

Alternate Names

Gemstone Groups

Key Separations

RI, birefringence, optic character and SG. Biaxial positive or negative with the common point halfway between highest RI and lowest RI.

Comments

Danburite can be chatoyant if it has parallel growth tubes.

Danburite Optical Properties

Transparency

Transparent - Translucent

Refractive Index

1.63-1.636
Tolerance:(+0.003/-0.003)

Birefringence

0.006

Optic Character

Biaxial

Optic Sign

Positive or Negative

Polariscope Reaction

Doubly Refractive (DR)

Fluorescence

SWUV: inert to weaker, light blue to blue-green
LWUV: inert to strong, light blue to blue-green

CCF Reaction

Pleochroism

Dichroic, unobservable or weak, varying shades of body color

Dispersion

Strength: weak fire Value: 0.016

Comments

Danburite Chemistry & Crystallography

Chemical Name

calcium boron silicate

Chemical Formula

CaB2(SiO4)2

Synthesis

Crystal System

Orthorhombic

Classification

Silicate

Nature

Natural

Crystallinity

Crystalline

Comments

Danburite Characteristic Physical Properties

Hardness

7

Streak

White

Specific Gravity

2.97-3.03 Typical:3

Toughness

Good

Inclusions

Danburite might have natural inclusions, fingerprints and parallel growth tubes.

Luster

Vitreous

Stability

Fracture

Uneven, Subconchoidal

Cleavage

None

Comments

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