Kaolinite
Kaolinite has been known since at least the Yuan (Mongol) dynasty in the century that is thirteenth “Kaolin earth”. It’s a “clay mineral”. Clay minerals are hydrous aluminium phyllosilicates, usually with adjustable 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 had been first properly described and known as in 1637 by Chinese scientist and encyclopedist Song Yingxing (1587-1666) whom lived during the Ming that is belated Dynasty. Kaolinite had been named for the ancient type that is chinese at the “Kao-Ling” Mine (from Gaoling, meaning high ridge), Jingdezhen Prefecture, Jiangxi Province, China. Kaolinite had been possibly the most mineral that is important clays found in pre-historic pottery. Kaolinite was introduced to the West by a priest that is french 1712.
Kaolinite is mainly present in public, in clay beds, usually with a bright color that is white. Kaolinite is simply too soft to be used as a gem by itself, but it’s available as inclusions in Quartz gems. The image above shows a Quartz that is faceted treasure beautiful inclusions of white Kaolinite. You will experience a magnified picture of white Kaolinite formations in the Quartz if you spot your cursor on the photo. This gem is from a discover that is present Madagascar.
Kaolinite distribution: pure material from many localities, including: at Kauling, Kiangsi Province, China. In many china-clay pits in Cornwall and Devon, England. At Limoges, Haute-Vienne, France. Near Dresden, Kemmlitz, and Zettlitz, Saxony, and elsewhere in Germany. Big deposits in the Donets Basin, Ukraine. In the USA, at Macon, Bibb County, Georgia; at the Dixie Clay Company mine, as well as in the Lamar Pit, near Bath, Aikin County, sc; 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.
| 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 | |||
| 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 |
| 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 |
| 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 |
