| Dictionary, Encyclopedia and Thesaurus - The Free Dictionary 3,920,593,573 visitors served. |
Dictionary/ thesaurus | Medical dictionary | Legal dictionary | Financial dictionary | Acronyms | Idioms | Encyclopedia | Wikipedia encyclopedia | ? |
Boracite |
Also found in: Dictionary/thesaurus, Wikipedia | 0.01 sec. |
|
|
boracite [′bȯr·ə‚sīt]
(mineralogy) Mg3B7O13Cl A white, yellow, green, or blue orthorhombic borate mineral occurring in crystals which appear isometric in external form; it is strongly pyroelectric, has a hardness of 7 on Mohs scale, and a specific gravity of 2.9. Boracite a mineral from the group of anhydrous borates. Chemical composition Mg3[B7O12]OCl. It contains 62.5 percent B2O3. It crystallizes into a rhombic (pseudocubic) sys-tem. The structure is of the complex shell type and contains [BO3]3- and (BO4)5-. Part of the Mg may be replaced by Fe2+. Boracite forms shiny crystals of cubic, tetrahedral, or dodecahedral appearance. The color is bluish-gray; frequently, it is colorless. Its hardness on the mineralogical scale is 7.5; its density is 2,930–2,950 kg /m3. Boracite is rare. It is formed in sedimentary deposits of gypsum, anhydrite, and potassium and rock salts. Want to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit the webmaster's page for free fun content. |
|
| Encyclopedia |
| Free Tools: |
For surfers:
Free toolbar & extensions |
Word of the Day |
Help
For webmasters: Free content | Linking | Lookup box | Double-click lookup |
|---|