Laponite is a syntheticsmectite clay invented in 1962 by clay scientistBarbara Neumann. Usually produced as powder, laponite is ananomaterial made up of very small disk-shaped crystals used in multiple industrial applications. Laponite was first marketed by the companyLaporte plc and is currently produced byBYK Additives & Instruments.[1][2][3][4][5] Laponite is not an approvedmineral species, since it is not naturally occurring and it is not produced by geological processes.[6]
In the first formulation of laponite created by Neumann in 1962, the synthetic clay was determined to be afluorohectorite and was produced in the form of discs 1 nanometer thick and with a diameter of 60 to 80 nanometers. This went into mass production in 1964.[7] The mineral structure of the clay gives laponite its particular physical characteristics and is similar to thesmectite group of clay minerals, with a 2:1 layered crystal structure in which two tetrahedral silica sheets lie either side of an octahedral sheet containing magnesium ions.[5] In 1966, Neumann patented a second formulation of laponite, called 'Laponite RD'. This form was free from fluorine, and has subsequently become the most widely used form of laponite.[8] This form of laponite has an empirical formula ofNa0.7[(Si8Mg5.5Li0.3)O20(OH)4].[5] In later years, Neumann also created other variants of laponite including a lithium-free magnesium silicate clay, a form of syntheticstevensite, and an iron silicate clay, which was a synthetic form ofnontronite.[7]