Staurolite
It can be identified in metamorphic rocks by its swiss cheese appearance (with poikilitic quartz) and often mantled porphyroblastic character.The name is derived from the Greek, stauros for cross and lithos for stone in reference to the common twinning.It occurs with almandine garnet, micas, kyanite; as well as albite, biotite, and sillimanite in gneiss and schist of regional metamorphic rocks.[9] Samples are also found in Island Park, Idaho, near Henrys Lake; Taos, New Mexico; near Blanchard Dam in Minnesota; and Selbu, Norway.Staurolite is one of the index minerals that are used to estimate the temperature, depth, and pressure at which a rock undergoes metamorphism.
Kola PeninsulaNesosilicateFormulaIMA symbolStrunz classificationCrystal systemMonoclinicCrystal classH-M symbolSpace groupCrystal habitTwinningCleavageFractureTenacityMohs scaleLusterStreakDiaphaneitySpecific gravityRefractive indexBirefringencePleochroism2V angleDispersionmineralMohs hardnessMagnesiummanganesetwinnedcrystalsporphyroblaststhin sectionsquartzmetamorphic rocksswiss cheesepoikiliticMadagascarregional metamorphicgarnetkyanitealbitebiotitesillimanitegneissschistofficial state mineralU.S. stateGeorgiaLepontine AlpsSwitzerlandFannin County, GeorgiaFairy Stone State ParkPatrick County, VirginiaIsland Park, IdahoHenrys LakeNew MexicoBlanchard DamMinnesotaindex mineralsBibcode