1) Oxide mineral 
Ixiolite is an accessory oxide mineral found in granitic pegmatites. It is an oxide with the general chemical formula (Ta,Nb,Sn,Mn,Fe)4O8 or (Ta,Nb,Sn,Mn,Fe)O2. ==Structure== Ixiolite was originally reported as crystallizing in the monoclinic crystal system. Detailed studies of the scandium, tin and titanium rich varieties indicate that they form ...