mineral

Kidney Stone (Urolith / Calcium Oxalate Stone)

Calcium Oxalate Monohydrate (Whewellite) / Calcium Oxalate Dihydrate (Weddellite)

AI-generated identification · may be incorrect

Hardness: 3.5-4 on Mohs scale. Color: Brownish, tan, yellow, or reddish-brown with crystalline/jagged or rounded concentric texture. Luster: Dull to vitreous. Structure: Microcrystalline aggregate.

Hardness: 3
Luster: Dull to vitreous

Identified July 26, 2026More mineral →

Explore Kidney Stone (Urolith / Calcium Oxalate Stone) in the encyclopedia →

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Physical properties

Hardness: 3.5-4 on Mohs scale. Color: Brownish, tan, yellow, or reddish-brown with crystalline/jagged or rounded concentric texture. Luster: Dull to vitreous. Structure: Microcrystalline aggregate.

Formation & geological history

Formed through biomineralization within the human urinary tract (kidneys) when urinary mineral salts (calcium, oxalate, uric acid) precipitate out of supersaturated urine.

Uses & applications

Biological mineral deposit (calculus); studied in medicine and biomineralogy.

Geological facts

Although formed inside a living organism rather than deep within Earth's crust, kidney stones consist of true mineral phases such as whewellite, weddellite, apatite, or cystine, making them biogenic minerals.

Field identification & locations

Identified by its small size (few millimeters), yellowish-brown to dark brown coloration, central cavity or concentric growth layers, and origin of passing from the body.