Browse Items (264 total)

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…

Taxonomy Phylum: Arthropoda Class: Trilobita Distinctive features Pygidium (tail) Thorax (body) Cephalon (head) Paired appendages (not often preserved) Three lobed longitudinal division of body (2x pleural, 1x axial) Calcitic exoskeleton Segmented…

Have a look at the ferruginous sandstone (L327) and the quartzite (L521) in the 1A Reference Series.

Have a look at the rhyolitic glass (L113) and the porphyritic andesite (L130) in the 1A Reference Series.

Have a look at quartz (M410, M411, M412) and calcite (M540, M541, M542) in the Reference Series.

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…