Browse Items (264 total)

Stratigraphic Range Ordovician to Permian Taxonomy Phylum: CnidariaClass: AnthozoaOrder: Rugosa Distinctive Features SeptaGrowth lines'Horn' shape Preservation Manmade cast

Have a look at the ferruginous arenite sandstone (L326) in the 1A Reference Series.

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…

Common alteration minerals include clays for plagioclase, serpentine for olivine, and chlorite for ferromagnesian minerals such as biotite.

Taxonomy Phylum: Mollusca Class: Cephalopoda Subclass: Ammonoidea Diagnostic features [See labelled diagram above] Aragonite shell Septa Suture (different for goniatites, ceratites and ammonites, see second diagram…

Have a look at the rhyolite glass (L113) in the 1A Reference Series.

Formula (Na,K)0-1Ca2(Mg,Fe2+,Fe3+,Al)5Si6-7.5Al2-0.5O22(OH)2 Structure Chain silicate Crystal System Crystal system: monoclinic (+) (-) Physical Properties Colour in hand specimen: black Cleavage: two at ~56° Hardness: 5-6 Optical…