COOKEITE ON QUARTZ (miniature)

Cookeite is an extremely rare mineral belonging to the silicate group and specifically the phyllosilicate subgroup, classified within the chlorite family, with the chemical formula LiAl4(Si3Al)O10(OH)8. This soft, low-density mineral exhibits a range of colors and features a crystalline structure composed of alternating layers of LiAl2(OH)6 and Al2O4(OH)2Si8O12, which can exist in multiple polytypes. Typically, cookeite is formed through the hydrothermal alteration of silicates found in pegmatites, occurring at relatively low temperatures, generally below 200 °C, and under varying pressure conditions.