| Anzaite-(Ce) | |
| Category: | Oxide mineral |
| Formula: | Ce4Fe2+Ti6O18(OH)2 |
| Imasymbol: | Anz-Ce[1] |
| System: | Monoclinic |
| Class: | Prismatic (2/m) (same H-M symbol) |
| Symmetry: | C2/m |
| Unit Cell: | a = 5.29, b = 14.58 c = 5.23 [Å]; β = 97.23° (approximated); Z = 1 |
| Color: | Grey |
| Habit: | Crystals (tiny) |
| Cleavage: | None |
| Tenacity: | Brittle |
| Mohs: | 6–6.5 |
| Diaphaneity: | Opaque |
| Density: | 5.05 (calculated; approximated) |
Anzaite-(Ce) is a rare-earth element (REE) oxide mineral with the formula Ce4Fe2+Ti6O18(OH)2.[2] [3] An example of chemically related mineral is lucasite-(Ce),[4] although it contains no iron. Cerium in anzaite-(Ce) is mainly substituted by neodymium, lanthanum, calcium and praseodymium. Titanium is substituted by niobium. Trace elements include thorium. The mineral is monoclinic, space group C2/m. Anzaite-(Ce) is hydrothermal mineral found in a carbonatite from the mineralogically prolific Kola Peninsula. The mineral name honors Anatoly N. Zaitsev, who is known for studies of carbonatites and REE.
Parent rocks for anzaite-(Ce) are silicocarbonatites of the Afrikanda alkali-ultramafic massif. These rocks underwent hydrothermal reworking, that beside anzaite-(Ce) produced also calcite, clinochlore, hibschite and titanite in expense of primary minerals.
Cerium in anzaite-(Ce) is substituted by significant amounts of neodymium, lanthanum, calcium, and praseodymium, with minor samarium and thorium. Other impurities in the mineral composition include niobium and silicon.
The crystal structure of anzaite-(Ce) characterizes in:
The disordered sites are located on the (010) planes, separated by ordered domains containing REE, VITi (octahedral) and two oxide-anion sites.