|
Click on a
letter above to view the list of gems. |
|
|
|
| Kaolinite
was named in 1637 by Chinese scientist and encyclopedist Song Yingxing
(1587-1666) for the ancient Chinese type locality at
the "Kao-Ling" Mine (from Gaoling, meaning high ridge),
Jingdezhen Prefecture, Jiangxi Province, China.
| Discovered
in ancient times; IMA
status:
Valid (pre-IMA; Grandfathered) |
|
Chemistry
|
|
|
Chemical
Formula: |
Al2Si2O5(OH)4
|
|
Aluminum
Silicate Hydroxide |
Molecular
Weight: |
258.16 gm
|
Composition: |
Aluminium |
20.90 % |
Al |
39.50 % |
Al2O3 |
|
Silicon |
21.76 % |
Si |
46.55 % |
SiO2 |
|
Hydrogen |
1.56 % |
H |
13.96 % |
H2O |
|
Oxygen |
55.78 % |
O |
|
|
|
|
100.00 % |
|
100.00 % |
= TOTAL OXIDE |
|
|
Classification
|
|
|
Mineral
Classification: |
Silicates (Germanates)
|
Strunz 8th
Ed. ID:
|
8/H.25-10
|
Nickel-Strunz 10th
Ed. ID:
|
9.ED.05
|
|
9 : SILICATES (Germanates)
E : Phyllosilicates D : Phyllosilicates with kaolinite layers composed of tetrahedral and octahedral nets
|
Related
to: |
Kaolinite-Serpentine Group.
Dickite,
Halloysite and Nacrite are polymorphs. Chemically identical to
Halloysite-7Å.
|
Members
of Group: |
Kaolinite-Serpentine Group:
Amesite, Antigorite, Baumite, Berthierine, Brindleyite,
Caryopilite, Chrysotile, Clinochrysotile, Cronstedtite,
Dickite, Fraipontite, Greenalite, Halloysite, Kaolinite,
Kellyite, Lizardite, Manandonite, Nacrite, Népouite,
Odinite, Orthochrysotile, Parachrysotile, Pecoraite,
Webskyite
|
Varieties: |
Chrome-Kaolinite,
Keramite (of Hunt), Parakaolinite
|
Synonyms: |
Ancudite,
Carnat, China Clay, Clayite (of Mellor), Cleîte,
Collyrinum, Collyrum, Creniadite, Fireclay, Kaolin,
Leucargilla, Marga Porcellana, Myelin, Neokaolin, Pholerite,
Porcelain Clay, Porcelain Earth
|
|
|
Crystal
Data
|
|
|
Crystallography:
|
Triclinic - Pedial
|
Crystal
Habit:
|
Rarely
as crystals, thin platy or stacked, to 2 mm. More commonly
as microscopic pseudohexagonal plates and clusters of
plates, aggregated into compact, claylike masses.
|
Twinning:
|
None
|
|
|
Physical
Properties
|
|
|
Cleavage: |
Perfect
on {001}
|
Fracture: |
Irregular/Uneven,
conchoidal, sub-conchoidal,
micaceous
|
Tenacity:
|
Sectile,
flexible but inelastic
|
Moh's
Hardness: |
2.0
- 2.5
|
Density:
|
2.61
- 2.68 (g/cm3)
|
Luminescence:
|
None
|
Radioactivity:
|
Not
Radioactive
|
|
|
Optical
Properties
|
|
|
Color: |
White to tan
or cream and pale-yellow; also often stained various hues
of tans and browns by impurities
|
Transparency: |
Transparent
to opaque, translucent as single crystals |
Luster: |
Waxy,
pearly to dull, earthy |
Refractive
Index: |
1.553
- 1.570 Biaxial ( - )
|
Birefringence: |
0.007
- 0.017
|
Dispersion: |
Weak; r
> v |
Pleochroism: |
None |
|
|
Occurances
|
|
|
Geological
Setting: |
Replaces
other aluminosilicate minerals during hydrothermal alteration
and weathering. A common constituent of the clay-size
fraction of sediments, where it may be formed by direct
precipitation. |
Common
Associations: |
Quartz,
Feldspar, Muscovite |
Common
Impurities: |
Fe,
Mg, Na, K, Ti, Ca, H2O
|
Type
Locality: |
Gaoling Mine (Kaoling Mine), Gaoling village, Ehu town, Fuliang County, Jingdezhen Prefecture, Jiangxi Province, China
|
Year
Discovered: |
Ancient
times. Known since the Yuan (Mongol) dynasty in
the thirteenth century. Named in 1637 |
View
mineral photos: |
Kaolinite
Mineral Photos and Locations |
|
|
Unusual
Gem Categories
|
|
|
|
Inclusions
in Quartz |
|
|
More
Information
|
|
|
|
Mindat.org
Webmineral.com
|
|
|
Kaolinite
has been known since at least the Yuan (Mongol) dynasty in
the thirteenth century as "Kaolin earth". It is a "clay mineral".
Clay minerals are hydrous aluminium phyllosilicates, often
with variable amounts of iron, magnesium, alkali metals
or alkaline earths. Kaolinite is typically white
to cream or pale-yellow or may often be stained various hues
of tans and browns by impurities.
Kaolinite
was first properly described and named in 1637 by Chinese scientist and encyclopedist Song Yingxing
(1587-1666) who lived during the late Ming Dynasty.
Kaolinite was named for the ancient Chinese type locality at
the "Kao-Ling" Mine (from Gaoling, meaning high ridge),
Jingdezhen Prefecture, Jiangxi Province, China. Kaolinite was
possibly the most important mineral in clays used in
pre-historic pottery.
Kaolinite was introduced to the West
by a French priest in 1712.
Kaolinite
is largely found in masses, in clay beds, usually with a bright white color.
Kaolinite is too soft to be used as a gem on its own,
but it is available as inclusions in
Quartz gems.
The picture above shows a faceted Quartz gem with beautiful
inclusions of white Kaolinite.
If you place your cursor over the picture you will see
a magnified picture of white Kaolinite formations in
the Quartz. This gem is from a recent find in Madagascar.
Kaolinite
distribution: pure
material from many localities, including: at Kauling,
Kiangsi Province, China. In numerous china-clay pits
in Cornwall and Devon, England. At Limoges, Haute-Vienne,
France. Near Dresden, Kemmlitz, and Zettlitz, Saxony,
and elsewhere in Germany. Large deposits in the Donets
Basin, Ukraine. In the USA, at Macon, Bibb County, Georgia;
at the Dixie Clay Company mine, and in the Lamar Pit,
near Bath, Aikin County, South Carolina; near Webster,
Jackson County, North Carolina; near Murfreesboro, Pike
County, and at Greenwood, Sebastian County, Arkansas;
from Mesa Alta, Rio Arriba County, New Mexico. At Huberdeau,
Quebec, and near Walton, Nova Scotia, Canada.
|
Kaolinite
gems for sale:
We
have not photographed our Kaolinite
gems yet. Please
check back soon.
|
|