Found 1 items, similar to natural indigo.
English → English (gcide) Definition: natural indigo Indigo \In"di*go\, n.; pl. Indigoes. [F. indigo, Sp. indigo, indico, L. indicum indigo, fr. Indicus Indian. See Indian.] [1913 Webster] 1. A kind of deep blue, one of the seven prismatic colors. [1913 Webster] 2. (Chem.) A blue dyestuff obtained from several plants belonging to very different genera and orders, such as, the woad, Isatis tinctoria (family Cruciferae), Indigofera suffroticosa, Indigofera tinctoria (family Leguminosae), Indigofera Anil, Nereum tinctorium, Polygonum tinctorium Ait. (family Polygonaceae), etc.; called also natural indigo. It is a dark blue earthy substance, tasteless and odorless, with a copper-violet luster when rubbed. Indigo does not exist in the plants as such, but is obtained by decomposition of the glycoside indican. [1913 Webster] Note: Commercial indigo contains the essential coloring principle indigo blue or indigotine, with several other dyes; as, indigo red, indigo brown, etc., and various impurities. Indigo is insoluble in ordinary reagents, with the exception of strong sulphuric acid. [1913 Webster] Chinese indigo (Bot.), Isatis indigotica, a kind of woad. Wild indigo (Bot.), the American herb Baptisia tinctoria which yields a poor quality of indigo, as do several other species of the same genus. [1913 Webster]