Difference between revisions of "Titanite"
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| Line 12: | Line 12: | ||
* Brittle, wedge-shaped monoclinic crystals | * Brittle, wedge-shaped monoclinic crystals | ||
| − | * | + | * Distinct cleavage in one direction; good in another |
| − | * Luster = | + | * Luster = adamantine to resinous |
* Fracture = conchoidal to splintery | * Fracture = conchoidal to splintery | ||
| − | * Streak = white | + | * Streak = reddish-white |
* Fluorescence = none | * Fluorescence = none | ||
| − | * Pleochroism = moderate to strong | + | * Pleochroism = moderate to strong trichroic (colorless - yellow to green - red to yellow-orange) |
| + | * Dispersion = very strong fire | ||
{| class="wikitable" | {| class="wikitable" | ||
| Line 31: | Line 32: | ||
|- | |- | ||
! scope="row"| Refractive Index | ! scope="row"| Refractive Index | ||
| − | | 1. | + | | 1.84 - 2.11 |
|- | |- | ||
! scope="row"| Birefringence | ! scope="row"| Birefringence | ||
Revision as of 14:31, 19 December 2022
Description
Small yellow, gray, green or brown crystals occasionally used as gemstones. Titanite, or sphene, is composed of calcium titanium silicate and is often associated with Granite. Deposits have been found in Canada (Ontario), Mexico, Austria (Tirol), Italy (Trentino), Norway, Switzerland, Madagascar, and the U. S. (New York, Montana, California). Sphene has good luster and fire but is too soft for general wear.
Synonyms and Related Terms
sphene; Titanit (Deut.); Sphen (Deut.); titanita (Esp.); titanite (Fr.); tytanit (Pol.); titanite, esfena (Port.); titaniet (Ned.)
Physical and Chemical Properties
- Brittle, wedge-shaped monoclinic crystals
- Distinct cleavage in one direction; good in another
- Luster = adamantine to resinous
- Fracture = conchoidal to splintery
- Streak = reddish-white
- Fluorescence = none
- Pleochroism = moderate to strong trichroic (colorless - yellow to green - red to yellow-orange)
- Dispersion = very strong fire
| Composition | CaTiSiO5 |
|---|---|
| Mohs Hardness | 5.0 - 5.5 |
| Density | 3.4-3.6 g/ml |
| Refractive Index | 1.84 - 2.11 |
| Birefringence | 0.100 - 0.135 (visible doubling) |
Comparisons
Natural and Simulated Diamonds
Resources and Citations
- Gem Identification Lab Manual, Gemological Institute of America, 2016.
- Mineralogy Database: Titanite
- Encyclopedia Britannica, http://www.britannica.com Comment: "sphene" [Accessed December 4, 2001]
- C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979
- Wikipedia: Titanite (Accessed Sept. 17, 2005 and Dec 2022)
- Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
- Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
- The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998