Latiumite Locality: Cava di Campagnano, Campagnano di Roma , Sacrofano Caldera, Rome Province , Latium , Italy ( Locality at mindat.org ) Size: 4.6 x 3.8 x 2.8 cm. This piece is a very classic specimen of this rare phyllosilicate. It features cream-white prismatic crystals of Latiumite measuring up to 5 mm on matrix. There are no localities for Latiumite outside of Italy, and it is only appropriate that this piece was named after the district in which it was first found. A great example of this classic material. Ex. Richard Kosnar Collection. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Latiumite
Latiumite is an IMA-recognized mineral species in the silicate class, with the chemical formula (Ca,K)₄(Si,Al)₅O₁₁(SO₄,CO₃).
It crystallizes in the monoclinic crystal system (space group P2_1). It is a member of the Latiumite structural group.
Key properties: Mohs hardness 5.5–6; specific gravity 2.93; Vitreous luster; optically biaxial.
IMA symbol Lat, grandfathered status — known before the IMA’s founding, named in 1953.
Found in blocks of metamorphosed limestone ejected by volcanism.
It is found associated with Hedenbergite, grossular-andradite, melilite, leucite, haÄ u yne, kaliophilite.
The name refers to the Latin name of the district of origin, Latium, Italy.