Cleusonite

Cleusonite is a member of the crichtonite group of minerals with the chemical formula (Pb,Sr)(U4+,U6+ )(Fe2+,Zn) 2(Ti,Fe2+,Fe3+ ) 18(O,OH) 38. This group of minerals contains approximately thirteen complex metal titanates. The structures of minerals of this group is complicated by frequent fine-scale twinning and metamictization due to radioactive elements. The crichtonite group consists of members of related mineral species of the type A{BC2D6E12}O38 which are characterized by their predominant cations (as seen in crichtonite (Pb), davidite (Na), loveringite (Ba), and mathiasite (K).