GO:0042629

Coarse, bluish-black staining cytoplasmic granules, bounded by a plasma membrane and found in mast cells and basophils. Contents include histamine, heparin, chondroitin sulfates, chymase and tryptase. [GOC:jl, http://www.ijp-online.com/archives/1969/001/02/r0000-0000tc.htm, PMID:12360215]