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9 Apr 2024: The olivine has decomposed to magnetite and serpentine. Relict olivine grains display characteristic curving cracks andClinopyroxene (augite). - ... Some simple twinning. Accessory minerals. - Opaque, interstitial, probably magnetite. Rock History.

9 Apr 2024: Some areof magnetite, clinopyroxene and other minerals. Extensive alteration along abundant cracks. ... Groundmass. - Fine-grained. Plagioclase feldspar needles, clinopyroxene, some olivine (mostly altered), and opaques, probably magnetite.

9 Apr 2024: Mica, biotite. hand specimen of biotite mica. Crystals of bioitie mica with perfect basal cleavage. Biotite sheet silicate crystal structure, CrystalMaker. Formula. K. 2. (Mg,Fe. 2+. ). 6-4. (Fe. 3+. ,Al,Ti). 0-2. [Si. 6-5. Al. 2-3. O. 20. ](OH,F).

9 Apr 2024: Bottryoidal hematite crystal. Hematite crystal strucutre, CrystalMaker. Formula. Fe. 2. O. 3. Structure. Non-silicate. Crystal System. Crystal system: trigonal (-). Physical Properties. Colour in hand specimen: black, steel-grey and bright to dull

14 Feb 2020: C. Synchrotron X-ray Diffraction from a mixture of Austenite, Ferrite and Hametite, Magnetite.

10 Apr 2011: When magnetite forms within the wall, a tubemay grow curved in an external magnetic field. ... 5D, with orange lepidocrocite, black magnetite,and GR2), just as in the tube wall.

14 Feb 2020: It has been demonstrated that cementite can be made by carburising magnetite (Fe.

9 Apr 2024: Minerals. Rocks comprise minerals. In order to understand the paragenesis of a rock, be it igneous, sedimentary or metamorphic, we must identify its constituent minerals. The aim of this collection is to detail the structural, physical and optical

9 Apr 2024: Browse Items (7 total). Tags: igneous. Sort by:. Formula Ca5(PO4)3(OH,F,Cl) Structure Non-silicate Crystal System Crystal system: hexagonal (-) Physical Properties Colour in hand specimen: green, white, yellow, blue brown etc.Hardness: 5 Optical

9 Apr 2024: Strongly pleochroic in reddish brown and pale straw. Often associated with small grains of an opaque accessory mineral, probably magnetite.

9 Apr 2024: Alteration to magnetite and serpentine, particularly along the curving cracks. Cracks across the thin-section, could be due to expansion of the rock as the olivine was altered.

9 Apr 2024: Halite cubic crystal structure with large Cl. -. anions (green) and small Na. cations (yellow). This mineral is commonly known as rock salt. Formula. NaCl. Structure. Non-silicate. Crystal System. Crystal system: cubic. Physical Properties. Colour

9 Apr 2024: Alteration. Zonation. Accessory minerals:. - Sphene. - Magnetite. - Apatite. Rock History.

9 Apr 2024: Alteration to magnetite and serpentine, particularly along the curving cracks. Cracks across the thin-section, could be due to expansion of the rock as the olivine was altered.

9 Apr 2024: Galena crystal structure, with large yellow sulfur and small purple lead symbols. Galena in hand specimen. Formula. PbS. Structure. Non-silicate. Crystal System. Crystal system: cubic. Physical Properties. Colour in hand specimen: lead grey. Streak:

9 Apr 2024: Gypsum single crystal hand specimen, monoclinic symmetry apparent. Milky, opaque gypsum with twinned crystal habit. Gypsum crystal structure showing monoclinic symmetry, CrystalMaker. Formula. CaSO. 4. 2H. 2. 0. Structure. Non-silicate. Crystal

9 Apr 2024: Sphene crystal structure, CrystalMaker. Formula. CaTi[SiO. 4. ](O, OH, F). Structure. Orthosilicate. Crystal System. Crystal system: monoclinic (). Physical Properties. Colour in hand specimen: colourless, yellow, green, brown or black. Cleavage: one

9 Apr 2024: Zircon crystal structure (tetragonal), CrystalMaker. Zircon is a common accessory mineral of many igneous rocks. Pleochroic haloes are formed by damage to the crystal lattice of enclosing minerals by the radioactive decay of elements such as Th and

9 Apr 2024: Garnet (euhedral) in hand specimen. Formula. (Mg,Fe,Ca). 3. Al. 2. Si. 3. O. 12. Structure. Orthosilicate. Crystal System. Crystal system: cubic. Physical Properties. Colour in hand specimen: typically red. Cleavage: none. Hardness: 6-7.5. Optical

9 Apr 2024: Pyrite crystals, with metallic lustre. Pyrite crystals within quartz. Pyrite cubis crystal structure, showing octahedral coordination of Fe by S. Formula. FeS. 2. Structure. Non-silicate. Crystal System. Crystal system: cubic. Physical Properties.