mineral

Kidney Stone

Calcium Oxalate (CaC2O4), Uric Acid, or Struvite

Hardness: 2.5-4 Mohs; Color: Tan, brown, or yellow; Luster: Dull to waxy; Crystal structure: Monoclinic or orthorhombic; Cleavage: None

Hardness: 2
Color: Tan, brown, or yellow
Luster: Dull to waxy

Identified May 7, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 2.5-4 Mohs; Color: Tan, brown, or yellow; Luster: Dull to waxy; Crystal structure: Monoclinic or orthorhombic; Cleavage: None

Formation & geological history

Formed in the human urinary tract via biomineralization. These occur when urine contains more crystal-forming substances than the fluid can dilute.

Uses & applications

Medical diagnostic specimen; used for laboratory analysis to determine the patient's metabolic health and dietary needs.

Geological facts

Kidney stones are medically known as nephrolithiasis. They can vary in size from a grain of sand to a golf ball. The largest kidney stone ever recorded weighed nearly 2 pounds.

Field identification & locations

Identified by their irregular, often jagged-edged appearance and organic coloring. Found in medical contexts following surgical removal or natural passing.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral