Iris Agate

Very finely banded, highly translucent Agate. Cut in thin slabs, it exhibits spectral hues when viewed in transmitted light.

Iris Agate is one of the most valuable varieties of Chalcedony. It is often cut into unique carvings to display iridescent effect.
General Information
A variety or type of:Agate, which is a variety of Chalcedony, which is a variety of Quartz
Physical Properties of Iris Agate
Mohs Hardness6.5 to 7
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Specific Gravity2.55 to 2.70
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Optical Properties of Iris Agate
Refractive Index1.530 to 1.543
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Optical CharacterUniaxial/+
gemdat.org, Management Team (2012)
Birefringence0.008 to 0.010
gemdat.org, Management Team (2012)
Colour
Colour (General)Iridescent, when sliced into a thin section it exhibits all the colours of the spectrum when viewed in transmitted light
Gemdat.org, Management Team (2012)
TransparencyTranslucent
Michael O’Donoghue, Gems, Sixth Edition (2006)
LustreWaxy
gemdat.org, Management Team (2012)
Crystallography of Iris Agate
Crystal SystemTrigonal
gemdat.org, Management Team (2012)
Further Information
Mineral information:Iris Agate information at mindat.org
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