|
Click on a
letter above to view the list of gems. |
|
| Chemistry:
LiAlSi4O10
[] | Discovered
in 1800;
IMA
status: Valid (pre-IMA; Grandfathered). The name Petalite is from
the Greek petalos meaning leaf in regard
to its perfect basal cleavage. The name for the crystals that
Petalite is cut from is Castorite, named after
Castor. Castor and Pollux
were heavenly twins and brothers of Helen of Troy from Greek mythology. |
|
Classification
|
|
|
Mineral
Classification: |
Silicates |
Strunz 8th
Ed. ID:
|
8/J.03-10
|
Nickel-Strunz 10th
Ed. ID:
|
9.EF.05 |
|
9 : SILICATES (Germanates) E : Phyllosilicates F : Single
nets with 6-membered rings, connected by M[4], M[8], etc.
|
Related
to: |
Petalite - Virgilite Series
|
|
|
Crystal
Data
|
|
|
Crystallography:
|
Monoclinic
- Prismatic
|
Crystal
Habit:
|
Crystals
tabular on [010], or elongated, to 2 m; some faces may
be striated. Commonly foliated cleavable, massive.
|
Twinning:
|
Common on [001], lamellar
|
|
|
Physical
Properties
|
|
|
Cleavage: |
[001]
Perfect, [201] Imperfect
|
Fracture: |
Imperfectly
Conchoidal
|
Tenacity:
|
Brittle
|
Hardness
(Mohs): |
6.0
- 6.5 |
Density:
|
2.412 - 2.422 (g/cm3) |
Luminescence:
|
Thermoluminescent |
Radioactivity:
|
Not
Radioactive
|
|
|
Optical
Properties
|
|
|
Color: |
Colorless,
White, Gray, Yellow, Pink
|
Transparency: |
Translucent
to Transparent |
Luster: |
Vitreous,
Pearly on cleavages |
Refractive
Index: |
1.504 - 1.523 Biaxial ( +
) |
Birefringence: |
0.0120 - 0.0140 |
Dispersion: |
Weak;
r > v |
Pleochroism: |
None |
|
|
Occurances
|
|
|
Geological
Setting: |
In
granite pegmatites, locally constituting an ore of lithium. |
Common
Associations: |
Albite,
Spodumene, Lepidolite, Microcline, Pollucite, Quartz,
Topaz, Tourmaline |
Common
Impurities: |
Mg,Fe,Na,Ca,K,H2O |
Type
Locality: |
Utö Island, Haninge, Södermanland, Sweden |
Year
Discovered: |
1800 |
View
mineral photos: |
Petalite
Mineral Photos and Locations |
|
|
More
Information
|
|
|
|
Mindat.org Webmineral.com |
|
|
Petalites
are beautiful colorless gems which are usually free
of inclusions. They are bright white and somewhat rare.
Petalite gems could be used in jewelry, but with care since
they are a bit brittle. Most gem quality Petalite is
currently coming from Brazil.
The name Petalite is from
the Greek petalos meaning leaf in regard
to its perfect basal cleavage. The name for the crystals that
Petalite is cut from is Castorite, named after
Castor. Castor and Pollux
were heavenly twins and brothers of Helen of Troy from Greek mythology.
Pollux is the basis for the naming of Pollucite.
The
main sources of gem quality crystals are Paprok, Nuristan Province,
Afghanistan; Bahia,
Northeast Region, Brazil; Minas Gerais, Southeast Region, Brazil; and Mogok, Sagaing District, Mandalay Division, Burma
(Myanmar).
|
Petalites
gems for sale:
We
have not photographed our Petalite gems yet. Please
check back soon!
|
|