Color:
Light to Dark green and yellowish green

Clarity: Type II
Optic Character: SR, often ADR
Cause of Color: Cr, Fe
Fluorescence: Inert
Fracture : Concoidal to uneven
Luster : Vitreous
Cleavage : None
Durability: Fair to Good

Characteristics for Identification:
Horsetail (byssolite) inclusions, high dispersion

Localities:
Italy, Korea, Rusia, Zaire

Demantoid
A Vaiety of Andradite Garnet
Ca₃ Fe₂ Si₃ O₁₂

Demantoid is a member of the garnet family. It is not only the most expensive of the garnets, it is one of the most expensive gems in the world! It is coveted for its rarity and its incredible brilliance. Demantoid is more dispersive than diamond. It's ability to break white light into rainbow colors is unsurpassed.
Demantoid occurs in many shades of green and ranges from slightly yellowish green to brownish green with a golden shine. The rarest and most valuable is a deep emerald green. Only a few stones achieve more than two carats after cutting. Demantoids from the Urals often include the diagnostic inclusions of asbestos fibres known as "horsetails". These inclusions are desirable.

Demantoid was first discovered in the Urals mountains in Russia in 1868.

Garnet Group Almandite Andradite Grossular Pyrope Spessartite Uvaravite

This gemstone is often confused with: Peridot Tsavorite Emerald Tourmaline Sphene Shalerite Glass Plastic

 

The Curious Lore of Precious Stones:
by George Frederick Kunz

Gemstone Buying Guide: A Guide to Buying
by Renee Newman