Purpurin

Purpurin or purpurine may refer to:
 * 1,2,4-Trihydroxyanthraquinone, a natural red/yellow dye found in the madder plant
 * Purpurin (protein), a protein, belonging to the lipocalin family
 * Purpurin (glass), a red or reddish-brown ancient type of glass
 * Purpurine, an earlier, but still occasionally seen, name for uroerythrin, the pink/red precipitate from urine