Cafetite

{{Short description|Titanium oxide mineral}}

{{Infobox mineral

| name = Cafetite

| category = oxide mineral

| image = File:Cafetite, Lizardite, Calcite-529437.jpg

| caption = Yellow cafetite crystals with green lizardite and calcite

| formula = {{chem|(Ca,Mg)|(Fe,Al)|2|Ti|4|O|12}}·{{chem|4(H|2|O)}}

| IMAsymbol=Cft{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=Mineralogical Magazine|volume=85|issue=3|pages=291–320|doi=10.1180/mgm.2021.43|bibcode=2021MinM...85..291W|s2cid=235729616|doi-access=free}}

| strunz = 4.FL.75

| dana =

| system = Monoclinic

| class = Prismatic (2/m)
(same H-M symbol)

| symmetry = P2₁/n

| unit cell = a = 4.944 Å,
b = 12.109 Å,
c = 15.911 Å;
β= 98.93°; Z = 8

| color = Pale yellow to colorless

| habit = Elongated columnar to acicular crystals, fibrous aggregates, pseudo-orthorhombic

| twinning =

| cleavage = Prismatic

| fracture =

| tenacity = Brittle

| mohs = 4–5

| luster = Adamantine

| refractive = n_α = 1.95, n_β = 2.08, n_γ = 2.11

| opticalprop = Biaxial (–), 2V=58°, Dispersion very strong, r > v

| birefringence = δ = 0.16

| 2V = Measured: 38°

| pleochroism = none

| streak = White

| gravity = 3.28

| density =

| melt =

| fusibility =

| diagnostic =

| solubility =

| diaphaneity = Semitransparent

| other =

| references = [https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Cafetite Mineralienatlas]

}}

Cafetite is a rare titanium oxide mineral with formula {{chem|(Ca,Mg)|(Fe,Al)|2|Ti|4|O|12}}·{{chem|4(H|2|O)}}. It is named for its composition, Ca-Fe-Ti.

It was first described in 1959 for an occurrence in the Afrikanda Massif, Afrikanda, Kola Peninsula, Murmanskaja Oblast, Northern Region, Russia.[http://www.mindat.org/min-850.html Mindat.org][http://rruff.geo.arizona.edu/doclib/hom/cafetite.pdf Handbook of Mineralogy] It is also reported from the Khibiny and Kovdor massifs of the Kola Peninsula and from Meagher County, Montana, US.

It occurs in pegmatites in a pyroxenite intrusion as crystals in miarolitic cavities. It occurs associated with ilmenite, titaniferous magnetite, titanite, anatase, perovskite, baddeleyite, phlogopite, clinochlore and kassite.