Fengchengite
Fengchengite is a rare mineral of the eudialyte group with the formula Na1236Fe33+Zr3Si32. The formula is simplified as it does not show the presence of cyclic silicate groups.
When compared to other minerals of the group, fengchengite characterizes in the presence of ferric iron and essential, site-dominating vacancies. The mineral was discovered in the Saima complex near Fengcheng city in China - hence its name.
