ORCIN  , a dioxytoluene, C6H3(

CH3)(OH)2 (i : 3 : 5), found in many lichens, e.g . Rocella tinctoria, Lecanora, and formed by fusing extract of aloes with potash . It may be synthesized from toluene; more interesting is its production when acetone dicarboxylic ester is condensed with the aid of sodium . It crystallizes in colourless prisms with one molecule of water, which redden on exposure . Ferric chloride gives a bluish-violet coloration with the aqueous solution . Unlike resorcin it does not give a fluorescein with phthalic anhydride . Oxidation of the ammoniacal solution gives orcein, C23H24N2O7, the chief constituent of the natural dye archil (q.v.) . Homo-pyrocatechinis an isomer (CH3: OH: OH= r : 3 : 4), found as its methyl ether (creosol) in beech-wood tar .