from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A relatively rare blue mineral, (Mg, Fe)Al2(PO4)2(OH)2, with a vitreous luster.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A semi-precious gemstone that is a basic phosphate of magnesium, iron and aluminium
from the GNU version of the Collaborative International Dictionary of English
- n. A mineral of a light indigo-blue color, occurring in small masses, or in monoclinic crystals; blue spar. It is a hydrous phosphate of alumina and magnesia.
from The Century Dictionary and Cyclopedia
- n. A mineral of a light- or indigo-blue color, crystallizing in the monoclinic system.
Medieval Latin lazulum, lapis lazuli; see lapis lazuli + -ite1.(American Heritage® Dictionary of the English Language, Fourth Edition)