Kidney Stone

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.

Identified on: 5/7/2026

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