Image: <bdi><a href="https://www.wikidata.org/wiki/Q56247090" class="extiw" title="d:Q56247090"><span title="mineral collector and dealer">Robert M. Lavinsky</span></a></bdi> (CC BY-SA 3.0)
monoclinicuncommonSilicates
Cookeite
LiAl₄(Si₃Al)O₁₀(OH)₈
This image displays a translucent, pale greenish-white to light green Cookeite specimen, exhibiting a platy habit and a distinct pearly luster.
Cookeite Physical Properties
Mohs Hardness
2.5Crystal System
monoclinicLuster
pearlyStreak Color
whiteCleavage
perfect on {001}Fracture
unevenSpecific Gravity
2.67Colors
white, pink, green, yellow, colorlessTransparency
transparentType Locality
Barra de Salinas district, Barra de Salinas, Coronel Murta, Jequitinhonha valley, Minas Gerais, Southeast Region, BrazilMineral Group
SilicatesUses
collector, minor lithium oreAssociated Minerals
tourmaline, lepidolite, quartz, albite, beryl, spodumeneRarity
uncommonGeological Context
Cookeite is a lithium-bearing chlorite group mineral typically found in lithium-rich granitic pegmatites, often forming as an alteration product of other lithium minerals or as a late-stage primary mineral.
