Aesthetic medicine is a discipline involving all medical methods, including the application of materials such as some clays, to skin for cosmetic purposes (e.g., to tighten skin, add/change color, stimulate circulation, or reduce a scar ). Such procedures are generally non-invasive or minimally invasive. Procedures that are non-invasive or minimally invasive are typical.
Cf., active principle, antibacterial clay, geotherapy, healing clay, medicinal clay, pelotherapy

An obsolete, local term for a fibrous talc from New York State, USA; or for pyrophyllite from China (also obsolete).

An obsolete term for pyrophyllite or a mixture with dominant pyrophyllite.

Ageing refers to a) a process where the physical properties, for example the rheology, of wet clay are improved by allowing the clay to sit undisturbed for a period, sometimes for years but more often for days or months, to allow the water to become more homogeneously distributed or to promote the growth of microorganisms. An improvement in plasticity by ageing is important for pressing and drawing of the clay for commercial production of ceramics.
Syn., aging, maturation; b) in soil mechanics, aging is also referred to the process of secondary consolidation or drained creep.
Cf., drained creep, secondary compression

A process of separating, fractionating, or manipulating fine particulate materials (or lighter particles) by gravitation in a vertically directed, usually upwards, moving air stream. This method is typically used for particles with sizes greater than 1ìm. The smaller or lighter particles rise to the top (overflow) above the coarser heavier fractions (underflow) because their terminal velocities are lower than the initial velocity of the rising fluid. The terminal velocities of various particle sizes in any media is calculated by Stokes’ law.
See also Stokes’ law;
Syn., elutriation

A process where kaolin is dried, transported on a column of rapidly moving air through a pulverization mill, and passed through a cyclonic air-classifier where coarse, sand-size particles are removed as gangue or returned to the mill for further size reduction. The term is used in the kaolin industry and refers to the less costly, dry-processed and air-classified powder products where bulk chemistry is of concern, but where purity, handling, and appearance may be less important.
Cf., air classification

See feldspar, alkali feldspars.

A regularly ordered interstratification of a talc-like layer and trioctahedral smectite-like layer in a ratio of 1:1 (Veniale and van der Marel, 1969; Bailey, 1981).
Cf., interstratification

An alkali activated clay involves the addition of alkali or alkaline earth metal hydroxide solutions such as NaOH, KOH or Ca(OH)2 to partly or completely dissolve clay mineral particles. Clay minerals are commonly calcined prior to alkali activation to increase the amount of dissolved species. After hardening, the product is a geopolymer, and the process is referred to as alkaline activation, although both alkali and alkaline earth elements may be involved.
Cf., activated clay, alkaline activated clay, geopolymer, thermally activated clay

Alkali feldspars represent a subgroup of feldspar minerals occurring in the solid solution series between albite [Ab: Na(Si3Al)O8] and orthoclase [Or: K(Si3Al)O8] end members. The series includes minerals of albite, sanidine (a high-temperature monoclinic polymorph of K-rich feldspar with disordered Al-Si distributions, occurs in lava flows), microcline (triclinic polymorph of K-rich feldspar, may be referred to as low, intermediate and high for variations in temperature of occurrence, and “maximum” with ordered Al-Si distributions), adularia (a K-rich feldspar with monoclinic and triclinic domains formed from partial Al-Si order states, often designated as a varietal name, occurs hydrothermally, in pegmatites and under diagenetic conditions), and orthoclase (a K-rich feldspar with an intermediate Al-Si ordering state, occurs in small plutons at moderate depths). The boundary between albite and sanidine is at ~ Or40 (i.e., ~ 40 mole % of K-rich feldspar) and this region between Ab90 to ~Or40 (with <10 mole % of anorthite component) is also defined as “anorthoclase”. Cf., feldspar