Smithsonite | Gemopedia

Smithsonite is named for James Smithson, the English founder of the Smithsonian Institution who first identified the mineral. Although it rarely forms crystals, smithsonite is most commonly found as botryoidal or stalactitic masses or as honeycombed aggregates. A member of the calcite group of minerals, smithsonite is prized for its variety of crystal forms. Smithsonite comes in a wide variety of colors depending on the impurities present. The presence of copper gives smithsonite its green to blue coloring. Trace amounts of cobalt are responsible for pink to purple hues while cadmium makes smithsonite yellow, and iron gives it a brown to reddish-brown color.
Alternate
Names
Bonamite
Colors
Green, Blue, Yellow, Brown, Pink, White To Colorless

Smithsonite Classification

Common Name

Smithsonite

Species

Smithsonite

Variety

Colors

Green, Blue, Yellow, Brown, Pink, White To Colorless

Alternate Names

Bonamite

Gemstone Groups

Key Separations

High birefringence high SG

Comments

Bonamite is the bluish green variety of smithsonite.

Smithsonite Optical Properties

Transparency

Transparent - Semitranslucent

Refractive Index

Over the Limit 1.621-1.849

Birefringence

0.225-0.228

Optic Character

Uniaxial

Optic Sign

Negative

Polariscope Reaction

Doubly Refractive (DR)

Fluorescence

SWUV: inert to strong green or red
LWUV: inert to strong white to yellowish white

CCF Reaction

Pleochroism

Unobservable

Dispersion

Strength: strong fire Value: 0.037

Comments

Smithsonite Chemistry & Crystallography

Chemical Name

zinc cabonate

Chemical Formula

ZnCO3

Synthesis

Crystal System

Trigonal

Classification

Carbonate

Nature

Natural

Crystallinity

Crystalline

Comments

Smithsonite Characteristic Physical Properties

Hardness

4-5

Streak

White

Specific Gravity

4-4.65 Typical:4.3

Toughness

Poor

Inclusions

Luster

Vitreous

Stability

Fracture

Uneven, Splintery

Cleavage

Perfect, in three directions

Comments

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