Name/Title
VesuvianiteEntry/Object ID
2023.7.52Description
Formula:Ca19Fe3+Al4(Al6Mg2)(◻4)◻[Si2O7]4[(SiO4)10]O(OH)9The formula is a partial simplification of the full structural formula. The large (VII-IX)-coordinated (X4)2(X3)8(X2)8(X1) sites are here combined (e.g. Ca19) and are typically filled with Ca, although other large cations such as the REE may be present. The square-pyramidal Y1 site can host a variety of M2+ and M3+ ions and is the basis for the distinction of several species. The VI-coordinated Y2 site typically is filled with Al, whereas the also VI-coordinated Y3 site may contain Al, Mg, and other cations of similar charge and size. The tetrahedral T1 site is typically vacant but may contain B (less commonly Al); the trigonal T2 site is also typically vacant but may also contain B. Some of the (SiO4) may be replaced by (H4O4), akin to the Si4+ ↔︎ 4H+ hydrogarnet substitution. Among the oxygen atoms that are not part of the silica tetrahedra, there are eight "O11" that typically occur as OH, two "O10" that are typically O & OH or OH & OH (the latter arrangement notably when Y1 is an M2+ cation). There may also be up to three "O12" that in most vesuvianite-group minerals are absent (and are not included here), but may be present particularly when T1 is occupied.Colour:Brown, yellow, brown-black, light green, emerald green, white, red, purple, violet, blue-green to blueLustre:Vitreous, ResinousHardness:6½Specific Gravity:3.32 - 3.43Crystal System:TetragonalMember of:Vesuvianite GroupName:Originally named "hyacinthus dictus octodecahedricus" by Moritz Anton Kappeler in 1723. Renamed "hyacinte du Vesuve" by Jean-Baptiste Louis Romé de L'Isle in 1772. This was possibly the inspiration for Abraham Gottlob Werner to rename the species "vesuvian" in 1795, after its discovery locality, Mount Vesuvius, Campania, Italy.
In 1799, Rene Just Haüy introduced the name "idocrase", which was formerly a popular name.Location
Location
Display Case
FS-9Room
Frieda Smith HallBuilding
Crater Rock MuseumDate
July 22, 2023