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85. Preface to Paul Magnette, La Citoyennete: une histoire de l’idee departicipation civique, Bruylant:Brussels 2001, v-vii.

9 Apr 2024: Clinopyroxene (augite). Phase diagram deomstrating the chemical compositional range for clinopyroxenes. Formula. (Ca,Mg,Fe. 2+. ,Fe. 3+. ,Ti,Al). 2. [(Si,Al). 2. O. 6. ]. Structure. Chain silicate. Crystal System. Crystal system: monoclinic ().

1 May 2004: Vesicles in prokaryotes have been described (48), a nucleus has beenfound in Gemmata obscuriglobus(42), and some bacteria are magnetotactic (12)with small, membrane-enclosed intracellular magnetite crystals that function likea

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: 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

16 May 2024: material called magnetite much later as a result of heating. ... The researchers think that the zircons were heated at this time, causing remobilization of iron and formation of magnetite.

9 Apr 2024: Anhydrite crystal structure, CrystalMaker. Formula. CaSO. 4. Structure. Non-silicate. Crystal System. Crystal system: orthorhombic (). Physical Properties. Colour in hand specimen: white or colourless when pure. Cleavage: two at 90. Hardness: 3-3.5.

16 May 2024: Two of the three grains (dated 3.97 Ga) contained magnetite, which preserved NRM, but had formed along cracks or damaged zones within the zircons. ... There is cause for optimism, however. We have now established the nanoscale tools that will enable us

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: Magnetite. Title. Magnetite. Subject. Magnetite is the most abundant oxide in igneous rock. ... Silver-black. Metallic lustre. No cleavage. Rock Specimens. Mineral Name. magnetite. iron oxide.

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

9 Apr 2024: Plagioclase feldspar. Plagioclase feldspar hand specimen, polycrystalline with opaque, white colour. Plagioclase feldspar with optical schiller. Plagioclase feldspar crystal structure, CrystalMaker. Formula. Na[AlSi. 3. O. 8. ] – Ca[Al. 2. Si. 2.

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.

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

9 Apr 2024: Browse Items (264 total). Page. of 27. Sort by:. Formula Fe3O4 Structure Non-silicate Crystal System Crystal system: cubic Physical Properties Colour in hand specimen: blackStreak: blackCleavage: noneHardness: 7.5-8 Optical Properties Colour in

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: 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: Mica, muscovite. Crystals of muscovite with basal cleavage. Crystals of muscovite, colourless. Muscovite crystal structure (a sheet silicate), CrystalMaker. Formula. K. 2. Al. 4. [Si. 6. Al. 2. O. 20. ](OH,F). 4. Structure. Sheet silicate. Crystal