BO'RAX, noun Sub-borate of soda; a salt formed by the combination of boracic acid with the marine alkali or soda. It is brought from the East Indies, where it is said to be found at the bottom or on the margin of certain lakes, particularly in Thibet. It is said to be artificially prepared in Persia, like niter. It comes in three states. 1. Crude borax tinkal, or chrysocolla, from Persia, in greenish masses of a greasy feel, or in opake crystals. 2. borax of China, somewhat purer, in small plates or masses, irregularly crystallized, and of a dirty white. 3. Dutch or purified borax in portions of transparent crystals, which is the kind generally used. It is an excellent flux in docimastic operations, a styptic in medicine, and useful in soldering metals.