20304 - Nice Agatized 1.63 Inch Cleoniceras sp Lower Cretaceous Ammonite Madagascar Amethyst Erythrite and annabergite (Ni3(AsO4)2·8H2O) (nickel

Erythrite and annabergite (Ni3(AsO4)2·8H2O) (nickel arsenate) form a complete series with the general formula (Co

Bronzati et al

Xenocyclopyge

Adastocephalum

Encrinuridae

20304 - Nice Agatized 1.63 Inch Cleoniceras sp Lower Cretaceous Ammonite Madagascar Amethyst Erythrite and annabergite (Ni3(AsO4)2·8H2O) (nickelCleoniceras sp, Parona and Bonarelli 1897 (ammonite) Cephalopoda Ammonitida Cleoniceratidae Cleoniceras is a rather involute, high whorled hoplitid from the Lower to basal Middle Albian of Europe, Madagascar, and Transcaspian region. The shell has a generally small umbilicus, arched to acute venter, and typically at some growth stage, falcoid ribs that spring in pairs from umbilical tubercles, usually disappearing on the outer whorls. These ammonites