Difference between revisions of "Fire opal"
Jump to navigation
Jump to search
(username removed) |
(username removed) |
||
| Line 14: | Line 14: | ||
|- | |- | ||
! scope="row"| Composition | ! scope="row"| Composition | ||
| − | | | + | | SiO2·nH2O |
|- | |- | ||
! scope="row"| Mohs Hardness | ! scope="row"| Mohs Hardness | ||
| Line 36: | Line 36: | ||
== Authority == | == Authority == | ||
| − | * | + | * Website address 1 Comment: Mineral Galleries at http://mineral.galleries.com/minerals/mineralo/opal/opal.htm Mohs hardness=5.5-6.0 |
* Wikipedia, the free encyclopedia, at http://www.wikipedia.com Comment: http://en.wikipedia.org/wiki/Opal (accessed Oct. 12, 2005) specific gravity=2.1=2.3; RI=1.44 -1.46; Mohs hardness=5.5-6.6 | * Wikipedia, the free encyclopedia, at http://www.wikipedia.com Comment: http://en.wikipedia.org/wiki/Opal (accessed Oct. 12, 2005) specific gravity=2.1=2.3; RI=1.44 -1.46; Mohs hardness=5.5-6.6 | ||
| − | * | + | * Yasukazu Suwa, ''Gemstones: Quality and Value, Volume 1'', Sekai Bunka Publishing Inc., Tokyo, 1999 Comment: RI=1.450; Specific gravity=2.15 |
| − | * | + | * Michael O'Donoghue and Louise Joyner, ''Identification of Gemstones'', Butterworth-Heinemann, Oxford, 2003 Comment: RI=1.45; Specific gravity=2.10 |
* ''Van Nostrand's Scientific Encyclopedia'', Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976 | * ''Van Nostrand's Scientific Encyclopedia'', Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976 | ||
Revision as of 06:41, 24 July 2013
Description
A brilliant red and orange opal. Fire opals have been mined in Mexico for over 500 years. Current mines in Mexico are at Queretaro and Magdalena.
Synonyms and Related Terms
girasol; Mexican opal; water opal; jelly opal; opala de fogo (Port.); Feueropal (Deut.)
Other Properties
Mineral system=amorphous Cleavage=none Fracture=conchoidal Luster=vitreous to resinous Streak=white Fluoresce=usually white or pale green, some samples phosphoresce
| Composition | SiO2·nH2O |
|---|---|
| Mohs Hardness | 5.5-6.0 |
| Density | 2.1-2.3 |
| Refractive Index | 1.44-1.46 |
Hazards and Safety
Higly hydrated; may be subject to dehydration and surface cracking.
Additional Information
Mineral Galleries: Website
Authority
- Website address 1 Comment: Mineral Galleries at http://mineral.galleries.com/minerals/mineralo/opal/opal.htm Mohs hardness=5.5-6.0
- Wikipedia, the free encyclopedia, at http://www.wikipedia.com Comment: http://en.wikipedia.org/wiki/Opal (accessed Oct. 12, 2005) specific gravity=2.1=2.3; RI=1.44 -1.46; Mohs hardness=5.5-6.6
- Yasukazu Suwa, Gemstones: Quality and Value, Volume 1, Sekai Bunka Publishing Inc., Tokyo, 1999 Comment: RI=1.450; Specific gravity=2.15
- Michael O'Donoghue and Louise Joyner, Identification of Gemstones, Butterworth-Heinemann, Oxford, 2003 Comment: RI=1.45; Specific gravity=2.10
- Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
- The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998