Iridescent Hematite
Image: <a rel="nofollow" class="external text" href="https://www.flickr.com/people/61111353@N00">Domenico Salvagnin</a> from Legnaro, Italy (CC BY 2.0)
Mineral NameIridescent Hematite
Chemical FormulaFe2O3
Mohs Hardness5.5
Crystal Systemtrigonal
Lustermetallic
Streak Colorreddish-brown
Cleavagenone
Fractureuneven
Specific Gravity5.26
Colorsdark grey, black, brown, blue, purple, green, gold, silver
Transparencyopaque
Type LocalityVolcanic regions worldwide
Mineral GroupOxides
Usescollector's specimens
Associated Mineralsbasalt, scoria, feldspar, pyroxene, olivine
Rarityuncommon
Description
A dark, vesicular volcanic rock surface covered in patches of thin, iridescent films displaying a spectrum of metallic rainbow colors, including blues, purples, greens, and golds.
Geological Context
This iridescent coating forms on volcanic rocks (like scoria or basalt) as a result of the oxidation of iron-rich minerals during cooling or subsequent weathering, creating thin films of hematite or goethite that cause interference colors.
