Hematoxylin
Description
A red crystalline component that is the coloring agent in logwood dye. Logwood dye, or hematoxylin, is contained in the heartwood of the logwood tree (Haematoxylum campechianum). The blood red extract is obtained by boiling the chips in water. It contains about 10% of the colorant hematoxylin along with resins and tannins. Hematoxylin oxidizes to form the reddish-brown metallic crystals of hematein that are insoluble in water. Using a variety of mordants, the extract can be prepared as a lake ranging in color from red to brown to navy (chrome), violet (alum) to black (iron). Logwood was used in black inks (iron gall ink, bichromate inks and watercolors. It is still used as a black dye for textiles and leather. Hematoxylin is also used as a histological stain in the preparation of organic tissues for microscopic examination.
Synonyms and Related Terms
logwood dye; Natural Black I; CI 75290; haematoxylin (Br.); hematoxilina (Esp., Port.); hydroxybrasilin; hematoxylon; haematin; hematin; blackwood; bluewood; palo de Campeche
Risks
- May be carcinogenic.
- Contact may cause irritation.
- Fisher Scientific: SDS
Physical and Chemical Properties
- Soluble in hot water, ethanol, glycerol and alkali hydroxides.
- Composition = C10H14O6-3H2O (mol. wt. = 302.28 g/mol)
- CAS = 517-28-2
- Melting Point = 100-120 C
Resources and Citations
- Helmut Schweppe, Schweppe color collection index and information book
- Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
- Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
- The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 4671
- The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998
- Conservation termlist: www.hants.org.uk/museums -
- Colour Index International online at www.colour-index.org
- Wikipedia: Haematoxylin Accessed Feb 2026
- Hektoen International From silks to science: the history of hematoxylin and eosin staining