Fire Agate

A particularly colourful variety of agate from Mexico, mostly with iridescent play of colour

Shop for Fire Agate

laguna achat agate

Origin of name: from its appearance which resembles red heat or fire

Can be confused with: due to its iridiscence fire agate can hardly be confused

Localities: only in central and northern Mexico and the southwestern USA (New Mexico, Arizona and California)

Handling: like all quartzes agate is sensitive to hydrofluoric acid only and generally unproblematic to work with

Worth knowing: the iridescence display of colour is due to the getting out of phase of light being reflected from alternating and parallel layers of silica and iron oxide, similar to the iridescence produced by oil on water.

Gemmological Properties of Fire Agate

Formula:
SiO2
Crystal system:
trigonal
Mohs hardness:
6.5 - 7
Specific gravity:
2.60 - 2.64
Refractive index:
birefringent 1.543 - 1.552
Max. Birefringence:
0.009
Dispersion:
none
Pleochroism:
none
Lustre:
waxy
Cleavage:
none
Fracture:
conchoidal, brittle