mineral
Vesuvianite (Idocrase)
Vesuvianite, Ca10(Mg,Fe)2Al4(SiO4)5(Si2O7)2(OH)4
AI-generated identification · may be incorrectOlive-green, granular to short-prismatic crystals with vitreous to resinous luster; Mohs hardness 6.5–7, generally poor cleavage, tetragonal crystal system, and specific gravity about 3.3–3.5. The specimen appears to be a natural crystal cluster, though exact identification would benefit from testing.
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Physical properties
Olive-green, granular to short-prismatic crystals with vitreous to resinous luster; Mohs hardness 6.5–7, generally poor cleavage, tetragonal crystal system, and specific gravity about 3.3–3.5. The specimen appears to be a natural crystal cluster, though exact identification would benefit from testing.
Formation & geological history
Forms mainly in contact-metamorphosed, calcium-rich rocks such as limestones and skarns, commonly during Mesozoic to younger metamorphic events. It crystallizes from hot, chemically reactive fluids near igneous intrusions.
Uses & applications
Transparent material may be cut as a gemstone; opaque clusters are primarily collector specimens. It has little major industrial or construction use.
Geological facts
Its alternate name, idocrase, comes from Greek roots meaning “mixed form,” referring to its varied crystal habits. Green vesuvianite can resemble epidote, grossular garnet, or diopside.
Field identification & locations
Look for olive-green color, high hardness, resinous luster, and compact tetragonal crystals in marble or skarn. Common localities include California, Quebec, Italy, Pakistan, Russia, and Norway.
