Difference between revisions of "Antigorite"
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== Description == | == Description == | ||
| − | A variety of [[serpentine|serpentine]] named after the community of Antigorio in Italy. Antigorite was was first described and named for a specimen from the Antigorio valley in the Novara province of Italy. | + | A variety of [[serpentine|serpentine]] named after the community of Antigorio in Italy. Antigorite was was first described and named for a specimen from the Antigorio valley in the Novara province of Italy. It is commonly used as a gemstone in jewelry and carvings. |
== Synonyms and Related Terms == | == Synonyms and Related Terms == | ||
| Line 12: | Line 12: | ||
* Monoclinic, crystals rare, usually massive | * Monoclinic, crystals rare, usually massive | ||
| − | * Cleavage = | + | * Cleavage = perfect |
* Fracture = conchoidal | * Fracture = conchoidal | ||
| − | * Luster = vitreous | + | * Luster = vitreous, greasy |
| − | * Streak = | + | * Streak = greenish-white |
* Low birefringence | * Low birefringence | ||
* May be translucent to opaque | * May be translucent to opaque | ||
| Line 23: | Line 23: | ||
|- | |- | ||
! scope="row"| Composition | ! scope="row"| Composition | ||
| − | | | + | | (Mg,Fe2+)3Si2O5(OH)4 |
|- | |- | ||
! scope="row"| Mohs Hardness | ! scope="row"| Mohs Hardness | ||
| Line 33: | Line 33: | ||
! scope="row"| Refractive index | ! scope="row"| Refractive index | ||
| 1.56-1.57 | | 1.56-1.57 | ||
| + | |- | ||
| + | ! scope="row"| Birefringence | ||
| + | | 0.005 - 0.006 | ||
|} | |} | ||
Revision as of 10:12, 5 January 2023
Description
A variety of Serpentine named after the community of Antigorio in Italy. Antigorite was was first described and named for a specimen from the Antigorio valley in the Novara province of Italy. It is commonly used as a gemstone in jewelry and carvings.
Synonyms and Related Terms
serpentine; antigorita (Esp.); antigorite (Port.); Antigorit (Deut.); antigoriet (Ned.)
Physical and Chemical Properties
- Monoclinic, crystals rare, usually massive
- Cleavage = perfect
- Fracture = conchoidal
- Luster = vitreous, greasy
- Streak = greenish-white
- Low birefringence
- May be translucent to opaque
- Translucent stones may show black inclusions, white veining, or moss-like shapes
| Composition | (Mg,Fe2+)3Si2O5(OH)4 |
|---|---|
| Mohs Hardness | 3.5 - 4.0 |
| Density | 2.5-2.6 g/ml |
| Refractive index | 1.56-1.57 |
| Birefringence | 0.005 - 0.006 |
Resources and Citations
- Mindat.org: antigorite
- Gem Identification Lab Manual, Gemological Institute of America, 2016.
- Thomas Gregory, The Condensed Chemical Dictionary, Reinhold Publishing, New York, 3rd ed., 1942
- G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 702
- B.Ford et al, Studies in Conservation, vol 39, pp. 57-69. for formula
- Wikipedia: Antigorite [Accessed Aug. 30 2005 and Dec 2022]