Ĭrack cocaine sold on the streets may be adulterated (or 'cut') with other substances mimicking the appearance of crack to increase bulk. Purer forms of crack will sink in water or melt at the edges when near a flame (crack vaporizes at 90 ☌, 194 ☏). Like cocaine in other forms, crack rock acts as a local anesthetic, numbing the tongue or mouth only where directly placed.
Purer forms of crack resemble off-white, jagged-edged 'rocks' of a hard, brittle plastic, with a slightly higher density than candle wax.
