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GLG Mineralogy
США
Добавлен 4 янв 2021
Mineral Identification : Staurolite and Andalusite
Luster - vitreous, sub vitreous, earthy
Streak - NA, harder than streak plate
Hardness - 6.5-7.5
Density - moderately dense
Cleavage - poor
Color - earthy tones, browns, black
Crystal system - andalusite = orthorhombic, staurolite = monoclinic
Crystal form/habit - staurolite perfect euhedral crystals, andalusite blocky and tabular
Extra notes - grey cross on andalusite formed by interstitial graphite (chiastolite), staurolite is commonly twinned (cruciform twinning)
Streak - NA, harder than streak plate
Hardness - 6.5-7.5
Density - moderately dense
Cleavage - poor
Color - earthy tones, browns, black
Crystal system - andalusite = orthorhombic, staurolite = monoclinic
Crystal form/habit - staurolite perfect euhedral crystals, andalusite blocky and tabular
Extra notes - grey cross on andalusite formed by interstitial graphite (chiastolite), staurolite is commonly twinned (cruciform twinning)
Просмотров: 4 047
Видео
Mineral Identification : Sillimanite and Kyanite
Просмотров 5 тыс.3 года назад
Luster - vitreous, (sillimanite sometimes earthy if weathered) Streak - white Hardness - sillimanite 7, kyanite variable hardness with orientation 4.5-7 Density - moderately dense Cleavage - sillimanite = perfect in 1 direction, Kyanite = perfect in 2 directions Color - white to variable, kyanite displays much stronger colors Crystal system - kyanite = triclinic, sillimanite = orthorhombic Crys...
Mineral Identification : Olivine
Просмотров 11 тыс.3 года назад
San Carlos Olivine Mantle Xenolith Nodules Luster - vitreous Streak - NA, harder than streak plate Hardness - 6.5-7 Density - moderate to moderately low Cleavage - none, conchoidal fracture Color - green Crystal system - orthorhombic Crystal form/habit - rarely in euhedral crystals Extra notes - color varies with Fe content, very brittle
Mineral Identification : Garnets
Просмотров 7 тыс.3 года назад
Almandine | Pyrope | Spessartine | Grossular Luster - Vitreous Streak - NA, too hard Hardness - variable, 6.5-7.5, scratches glass Density - moderate to moderately low density, almandine the densest, grossular least dense Cleavage - none, conchoidal fracture Color - highly variable! Crystal system - isometric Crystal form/habit - euhedral high symmetry ball forms Extra notes - can often be foun...
Mineral Identification : Sorosilicates and Cyclosilicates
Просмотров 4,3 тыс.3 года назад
Beryl | Epidote | Tourmaline Luster - Vitreous Streak - white, if not harder than the streak plate Hardness - beryl (7.5-8), tourmaline (7-7.5), epidote (6-7) Density - moderately low Cleavage - imperfect or poor, epidote is perfect in one direction Color - variable! Beryl = pale colors, tourmaline highly variable and often bicolored, epidote = pistachio green Crystal system - beryl (hexagonal)...
Mineral Identification : Amphiboles
Просмотров 17 тыс.3 года назад
Hornblende | Tremolite | Actinolite | Glaucophane Luster - vitreous Streak - white, if not harder than the streak plate Hardness - 5-6 Density - moderately dense Cleavage - two perfect planes at 56 and 124 degrees Color - hornblende = black, tremolite- actinolite defined by green variability, glaucophane is noticeably grey blue Crystal system - monoclinic Crystal form/habit - bladed, fibrous, e...
Mineral Identification : Pyroxenes
Просмотров 9 тыс.3 года назад
Diopside | Augite | Enstatite | Jadeite Luster - vitreous to sub vitreous Streak - white, or too hard to powder Hardness - 5.5-7 Density - moderately low Cleavage - two good angles at ~90 degrees Color - variable but usually green, brown, black Crystal system - monoclinic (enstatite = orthorhombic) Crystal form/habit - euhedral crystals (jadeite = polycrystalline) Extra notes - jadeite tends to...
Minerals : Phyllosilicates - Talc
Просмотров 5 тыс.3 года назад
Luster - pearly Streak - white Hardness - 1 Density - low density Cleavage - NA Color - white, pale, pastels Crystal system - monoclinic Crystal form/habit - massive, blocky, fibrous Extra notes - soft to the touch, silky
Minerals : Phyllosilicates - Biotite, Muscovite, Lepidolite, Chlorite
Просмотров 10 тыс.3 года назад
Luster - vitreous Streak - white, very pale brown (biotite) Hardness - 3-4 Density - moderately low Cleavage - perfect 1 direction, parallel sheets Color - variable, black (biotite), white (muscovite), pink/lavender (lepidolite), green (chlorite) Crystal system - monoclinic Crystal form/habit - sheets, books, pseudo-hexagonal Extra notes - we mainly use color to distinguish
Minerals : Phyllosilicates - Kaolinite
Просмотров 6 тыс.3 года назад
Luster - earthy Streak - white Hardness - 2-2.5 Density - very low density Cleavage - NA Color - white Crystal system - triclinic Crystal form/habit - massive, blocky Extra notes - readily powder-able
Mineral : Phyllosilicates - Serpentine
Просмотров 12 тыс.3 года назад
Luster - pearly, earthy, vitreous, waxy Streak - white Hardness - highly variable Density - moderately low Cleavage - NA Color - green, yellow, brown Crystal system - monoclinic Crystal form/habit - fibrous, blocky, massive, layered Extra notes - fibrous and potentially dangerous, heavily altered
Mineral : Tectosilicates - Plagioclase Feldspars
Просмотров 7 тыс.3 года назад
Luster - vitreous Streak - white Hardness - 6-6.5 Density - moderately low density Cleavage - two planes @ 90 degrees Color - variable, white-grey-dark, labradorescence Crystal system - triclinic Crystal form/habit - blocky, massive Extra notes - you can expect visible lamallae that are very straight, and a play of colors in labradorite
Mineral : Tectosilicates - Alkali Feldspars
Просмотров 12 тыс.3 года назад
Luster - vitreous, sub vitreous Streak - white Hardness - 6-6.5 Density - moderately low density Cleavage - two planes at 90 degrees Color - variable, beige-blue-pink-off white Crystal system - orthoclase = monoclinic, microcline = triclinic Crystal form/habit = orthoclase = euhedral, microcline = massive/blocky Extra notes - look for exsolution in microcline
Mineral :Tectosilicates - Opal
Просмотров 1,3 тыс.3 года назад
Luster - vitreous Streak - white Hardness - 5-6 Density - low density Cleavage - none Color - variable Crystal system - amorphous Crystal form/habit - forms in veins and pockets Extra notes - conchoidal fracture, internal light diffraction produces a play of colors
Minerals : Tectosilicates - Quartz
Просмотров 3,7 тыс.3 года назад
Luster - Vitreous Streak - white Hardness - 7 Density - moderatley low Cleavage - none Color - variable, usually pale colors Crystal system - hexagonal Crystal form/habit - polycrystalline, terminated hexagonal prism, microcrystalline Extra notes - conchoidal fracture