Cookeite is a mineral species of the silicate group and the phyllosilicate subgroup, part of the chlorite family, with the formula LiAl4(Si3Al)O10(OH)8. This soft, low-density mineral of variable color has a crystalline structure made up of alternating layers LiAl2(OH)6 and Al2O4(OH)2Si8O12 having several polytypes. Cookeite is often found as a product of hydrothermal alteration of silicates in pegmatites. It forms at relatively low temperatures (below 200°C) and variable pressures.
{{Infobox mineral|name=Cookeite|image=Cookeite.jpg|caption=Cookeite on quartz, Paris, Maine, topotype deposit|category= Phyllosilicate minerals|group=Chlorite group|formula=|strunz=09.EC.55|system=monoclinic|dana=71.04.01.02|class=prismatic;C2 or Cc|color=white, green, brown, golden, pink|twinning=around [310]|cleavage=perfect over {001}|fracture=flexible|tenacity=2,5|luster=pearly; silky|refractive=α = 1,572–1,576, β = 1,579–1,584, γ = 1,589–1,6|birefringence=biaxial (+), 0,0170–0,02402V = 35 to 60°|pleochroism=x = y: pale green to pink, z: colorless to pale yellow|fluorescence=cream yellow (SW)|density=from 2.58 to 2.69}}
Cookeite is a mineral species of the silicate group and the phyllosilicate subgroup, part of the chlorite family, with the formula LiAl4(Si3Al)O10(OH)8. This soft, low-density mineral of variable color has a crystalline structure made up of alternating layers LiAl2(OH)6 and Al2O4(OH)2Si8O12 having several polytypes. Cookeite is often found as a product of hydrothermal alteration of silicates in pegmatites. It forms at relatively low temperatures (below 200°C) and variable pressures.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).