Piss crystals 

The accumulated solids from dried piss. Often found on extremely neglected toilets, or more rarely, in unwashed bodily crevices.

I lifted the seat, and the rim was glistening with piss crystals.

Piss crystals by Mousetower March 4, 2011

Piss crystals 

A synonym for meth because meth can be yellow and look like as if urine was a crystal

Used like - Thats some good piss crystals man.

Piss crystals by Big schlong No March 28, 2021