Ivory | Gemopedia

Ivory has long been treasured for its beautiful white color and ability to be finely carved. As opposed to bone or horn, ivory is derived from the teeth and tusks of animals. Because of the devastating impact of poaching due to the ivory trade, the importation and sale of such materials is severely restricted or banned in many countries.
Colors
White To Light Yellow

Ivory Classification

Common Name

Ivory

Species

Ivory

Variety

Colors

White To Light Yellow

Alternate Names

Gemstone Groups

Key Separations

RI, magnification, SG and possible fluorescence

Comments

The trade on new elephant ivory has been banned sine 1991.Mammoth or mastodon ivory can have a hardness up to 5 and an SG up to 3.00. Walrus ivory can only be processed and sold by the Inuit of North America and Greenland.Currently the Canadian Department of Fisheries and Oceans restricts the export of narwhal tusks but the Inuit traders are challenging the ban in court. The United States restricts the import of walrus and narwal ivory. More information about the ivory ban can be found at http://www.cites.org/.

Ivory Optical Properties

Transparency

Translucent - Opaque

Refractive Index

1.535-1.54

Birefringence

Optic Character

Optic Sign

Polariscope Reaction

Aggregate (AGG)

Fluorescence

SWUV: weak to moderate bluish white or violet blue
LWUV: weak to strong bluish white or violet blue

CCF Reaction

Pleochroism

None

Dispersion

Comments

Ivory Chemistry & Crystallography

Chemical Name

calcium hydroxyl phosphate

Chemical Formula

Dentine from teeth or modified teeth of mammals such as elephant, mammoth, hippopotamus, warthog, narwal or walrus

Synthesis

Crystal System

NA

Classification

Organic

Nature

Natural

Crystallinity

Amorphous

Comments

Ivory Characteristic Physical Properties

Hardness

2.2-2.8

Streak

White

Specific Gravity

1.7-2

Toughness

Fair

Inclusions

Elephant and mammoth ivory will have wavy or intersecting curved lines in a v shaped pattern called engine turning effect. Mammoth or Moscow ivory tends to have more cracks than modern ivory. Walrus ivory or sea ivory is oval in cross section and the center has a rough bumpy appearance. Whale ivory comes from the teeth of sperm whales and can be found in antique Inuit carvings and scrimshaw. Narwhal ivory is hollow in the middle and tree-ring like growth patterns and a right to left spiral pattern.

Luster

Greasy

Stability

Fracture

Splintery

Cleavage

None

Comments

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