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Cummingtonite

Cummingtonite

  Hand Specimen identification: Prismatic habit, two perfect cleavages intersecting at near 60° when viewed in basal section, habit, color (if light brown), and association identify cumming-tonite. It may be confused with other amphiboles, especially anthophyllite and gedrite. Chemical Composition :(Mg,Fe) 7Si8O22(OH)2 Hardness : 51 2 to 6 Specific Gravity2.9 to …

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Grunerite

Grunerite is an end member of the cummingtonite-grunerite series. Structure and composition are anal-ogous to cummingtonite. The name grunerite is by definition restricted to compositions close to end member Fe7Si8O22(OH)2.

  Hand Specimen identification: Habit, color, two prominent cleavages at 56° to each other, and association help identify grunerite, but it cannot be distinguished from other members of the cummingtonite series without chemical or X-ray analysis. Chemical Composition :Fe7Si8O22(OH)2 Hardness : 6 Specific Gravity3.1 to 3.6 Cleavage/Fracture : two perfect prismatic{110}/uneven …

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Spodumene

LiAlSi2O6 Origin of Name : From the Greek word spodoumenos, meaning “ashes.” Hand Specimen Identification Spodumene is typically found in pegmatites where it may  form very large crystals. Prismatic cleavage,hardness, color, and association help identify it, but it may be difficult to tell from feldspar or scapolite. it often has …

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Spodumene

Hand Specimen identification: Spodumene is typically found in pegmatites where it may form very large crystals. Prismatic cleavage, hardness, color, and association help identify it, but it may be difficult to tell from feldspar or scapolite. it often has the appearance of a log or of petrified wood. Chemical Composition …

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Cummingtonite

Hand Specimen identification: Prismatic habit, two perfect cleavages intersecting at near 60° when viewed in basal section, habit, color (if light brown), and association identify cummingtonite. It may be confused with other amphiboles, especially anthophyllite and gedrite. Chemical Composition : (Mg,Fe) 7Si8O22(OH)2 Hardness : 51 2 to 6 Specific Gravity2.9 …

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Lepidolite

Hand Specimen identification: Micaceous habit (see Figure 11), often a distinctive lilac-gray or rose color, and association usually serve to identify lepidolite. Chemical Composition : K(Li,Al) 2 – 3(AlSi 3O10)(OH)2 Hardness : 2.5 to 4 Specific Gravity2.9 Cleavage/Fracture : perfect basal {001}/uneven Luster/Transparency : pearly/translucent Color : perfect basal {001}/uneven …

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Chlorite

Hand Specimen identification: Deep green color, and micaceous habit and cleavage are usually adequate to identify chlorite. The many individual species and varieties are difficult to tell apart. Chlorite is sometimes confused with talc. Chemical Composition : (Mg,Fe,Al)6(Si,Al)4O10(OH)8 Hardness : 2 to 21 2 Specific Gravity3 Cleavage/Fracture : perfect basal …

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Prehnite

Hand Specimen identification: Prehnite, although not a zeolite, occurs in many of the same places that zeolites occur. When green and botryoidal (typical) it is easily identified. Otherwise it may be difficult to distinguish from zeolites, and may also be confused with hemimorphite and smithsonite. Chemical Composition : Ca2Al(AlSi 3O10)(OH)2 …

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Apophyllite

Hand Specimen identification: Like prehnite, apophyllite often occurs where zeo-lites occur. Perfect one direction of cleavage, form, color, and luster help identify it. Chemical Composition : KCa4Si8O20F#8H2O Hardness : 41 2 to 5 Specific Gravity2.3 Cleavage/Fracture : one perfect (001), poor{110}/uneven Luster/Transparency : pearly/transparentto translucent Color : colorless, white, gray …

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Enstatite

Hand Specimen identification: Association, luster, color, and two cleavages at about 90° to each other identify pyroxene, but distinguishing enstatite from other pyroxenes can be problematic. Exact composition cannot be determined without additional analytical data. It may also be confused with amphibole, but the latter has two cleavages at about …

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