rhino pee crystals

From my Tiny Worlds Collection, this photomicrograph is composed of naturally occurring crystals in the urine of a Black Rhinoceros. The urine was collected for routine health monitoring. Afterwards, the specimen is retained for crystal formation and photography. The crystal is likely a calcium salt. The colorless crystals get their color when polarized light is used above and below the specimen. Horses have similar crystals.

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