Browse Items (4 total)

Formula (K,Na)[AlSi3O8] Structure Framework silicate Crystal System Crystal system: monoclinic (-) or triclinic (+) (-) Physical Properties Colour in hand specimen: white or pink Cleavage: two at 90° Hardness: 6-6.5 Optical…

Formula (Na,Ca)(Mg,Fe,Mn,Li,Al)3(Al,Mg,Fe3+)6[Si6O18](BO3)3(O,OH)3(OH,F) Structure Ring silicate Crystal System Crystal system: trigonal (-) Physical Properties Colour in hand specimen: blackHardness: 7 Optical Properties Colour in…

Formula Zr[SiO4] Structure Orthosilicate Crystal System Crystal system: tetragonal (+) Physical Properties Colour in hand specimen: reddish brown, yellow, grey, green or colourlessHardness: 7.5 Optical Properties Colour in…

Hand Specimen Medium to coarse-grained rock with a granular texture. White feldspar laths 2-4 mm long are clearly visible. Other phases: pink feldspar, black biotite mica, black hornblende amphibole and pale grey quartz. These grains are…