Kaolinite

Compared with other clay minerals, kaolinite is chemically and structurally simple. It is described as a 1:1 or TO clay mineral because its crystals consist of stacked TO layers. Each TO layer consists of a tetrahedral (T) sheet composed of silicon and oxygen ions bonded to an octahedral (O) sheet composed of oxygen, aluminum, and hydroxyl ions. The T sheet is so called because each silicon ion is surrounded by four oxygen ions forming a tetrahedron. The O sheet is so called because each aluminum ion is surrounded by six oxygen or hydroxyl ions arranged at the corners of an octahedron. The two sheets in each layer are strongly bonded together via shared oxygen ions, while layers are bonded via hydrogen bonding between oxygen on the outer face of the T sheet of one layer and hydroxyl on the outer face of the O sheet of the next layer. A kaolinite layer has no net electrical charge and so there are no large cations (such as calcium, sodium, or potassium) between layers as with most other clay minerals. This accounts for kaolinite's relatively low ion exchange capacity. The close hydrogen bonding between layers also hinders water molecules from infiltrating between layers, accounting for kaolinite's nonswelling character. When moistened, the tiny platelike crystals of kaolinite acquire a layer of water molecules that cause crystals to adhere to each other and give kaolin clay its cohesiveness. The bonds are weak enough to allow the plates to slip past each other when the clay is being molded, but strong enough to hold the plates in place and allow the molded clay to retain its shape. When the clay is dried, most of the water molecules are removed, and the plates hydrogen bond directly to each other, so that the dried clay is rigid but still fragile. If the clay is moistened again, it will once more become plastic.

The main use of the mineral kaolinite (about 50% of the time) is the production of paper; its use ensures the gloss on some grades of coated paper. Kaolin is also known for its capabilities to induce and accelerate blood clotting. In April 2008 the US Naval Medical Research Institute announced the successful use of a kaolinite-derived aluminosilicate infusion in traditional gauze, known commercially as QuikClot Combat Gauze, which is still the hemostat of choice for all branches of the US military. Kaolin is used (or was used in the past): in ceramics (it is the main component of porcelain) in toothpaste as a light-diffusing material in white incandescent light bulbs in cosmetics in industrial insulation material called Kaowool (a form of mineral wool) in 'pre-work' skin protection and barrier creams in paint to extend the titanium dioxide (TiO2) white pigment and modify gloss levels for modifying the properties of rubber upon vulcanization in adhesives to modify rheology in organic farming as a spray applied to crops to deter insect damage, and in the case of apples, to prevent sun scald as whitewash in traditional stone masonry homes in Nepal (the most common method is to paint the upper part with white kaolin clay and the middle with red clay; the red clay may extend to the bottom, or the bottom may be painted black) as a filler in Edison Diamond Discs as a filler to give bulk, or a coating to improve the surface in papermaking as an indicator in radiological dating since kaolinite can contain very small traces of uranium and thorium to soothe an upset stomach, similar to the way parrots (and later, humans) in South America originally used it (more recently, industrially-produced kaolinite preparations were common for treatment of diarrhea; the most common of these was Kaopectate, which abandoned the use of kaolin in favor of attapulgite and then (in the United States) bismuth subsalicylate (the active ingredient in Pepto-Bismol)) for facial masks or soap (known as "White Clay") as adsorbents in water and wastewater treatment to induce blood clotting in diagnostic procedures, e.g. Kaolin clotting time in its altered metakaolin form, as a pozzolan; when added to a concrete mix, metakaolin accelerates the hydration of Portland cement and takes part in the pozzolanic reaction with the portlandite formed in the hydration of the main cement minerals (e.g. alite) in its altered metakaolin form, as a base component for geopolymer compounds

Kaolinite is said to aid detoxification, removing impurities from the body and strengthening the possessor's energy. Placing this stone at the crown chakra may heighten spirituality and assist in communicating with higher spiritual beings. It's also said to connect with the third eye, heart, and throat chakras, increasing awareness, love, and openness when communicating.