Ruby
Ruby is an oxide mineral valued for its hardness and gem potential, with known Chinese sources.
About Ruby
Ruby belongs to the oxide class in the corundum group and has the chemical formula Al₂O₃. It crystallizes in the trigonal system and ranks among the harder species, with lasting durability. Its combination of structural character and global distribution make it a recognized species in both systematic and aesthetic collections.
Identification & care
Crystals commonly develop as tabular to prismatic hexagonal crystals; barrel-shaped; massive. Its color is typically red. The luster is vitreous, adamantine, the streak is white, and specimens range from transparent to opaque. The cleavage is none — parting on {0001} and {1011}. The fracture is conchoidal, which aids identification.
Collector context
How it forms
In terms of geology, Ruby forms in metamorphic rocks (marble), alluvial deposits; also basaltic intrusions. It is commonly found in association with spinel, calcite, dolomite, graphite, phlogopite.
Classic Chinese localities
Ruby has known Chinese occurrences in Yunnan.
Why collectors care
Ruby occupies a rare position: it matters equally to specimen collectors and to the gem trade. Crisp natural crystals with saturated color and good clarity command premium pricing and are among the highest-prestige targets in any systematic collection.
What affects value
Value in Ruby is assessed, in typical order of weight, against: (1) locality provenance; (2) crystal size; (3) transparency and internal clarity; (4) color intensity and saturation; (5) crystal form and termination sharpness; (6) matrix and associated-species aesthetics; (7) gem-cutting potential. Verified locality documentation and cutting potential further elevate collector demand.
Naming history
The name Ruby has a specific etymological and historical context — see Mindat's reference entry for provenance details. We have retained naming data at the record level; published prose is paraphrased from factual fields rather than copied from source.