Home / admin

admin

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 …

Read More »

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 …

Read More »

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 …

Read More »

Seismic Wave Types

Seismic waves can also be labeled by the paths they take in the Earth. Body waves (P or S) travel through the interior of the Earth. Surface Waves travel along the Earth surface. Their speeds are slower and their amplitudes decrease slowly with distance compared to the body waves. Two …

Read More »

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 …

Read More »

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 …

Read More »

Jadeite

Hand Specimen identification: Association with other high-pressure minerals, form, two (rarely seen) cleavages at near 90°, green color, and tenacity identify jadeite. It is distinguished from nephrite by its luster. An optical microscope may be needed to confirm identification. Chemical Composition : NaAlSi2O6 Hardness : 61 2 to 7 Specific …

Read More »

Augite

Hand Specimen identification: Association, form, two cleavages at 86° to 87°, and color identify pyroxene, but differentiating augite is problematic without X-ray data. White to green or pale green pyroxenes are often diopside; augite tends to be dark green or black. Augite is occasion-ally confused with hornblende. Plate 6.1 is …

Read More »

Pigeonite

Hand Specimen identification: Occurrence as phenocrysts in volcanic rock, form, two cleavages at 86°, and color identify pyroxene, but telling pigeonite from the other dark-colored pyroxenes is difficult. Only X-ray studies can make the distinction. Chemical Composition : (Ca,Mg,Fe)2Si2O6 Hardness : 6 Specific Gravity3.4 Cleavage/Fracture : two perfect prismatic {110}/uneven …

Read More »