09-17. Titanite #1.
Titanite – Sphene for gemologists has been known since the late 1700s and can be found on all continents. It will be the mineral of week 38 of this short tour of the geometry of Nature.
Titanite was renamed “sphene” by a French mineralogist in the 1800s. Maybe its cognac or chartreuse yellowish green color had something to do with it – the story doesn’t say. Renamed titanite again in 1982, both names are still in use.
Titanite is a small monoclinic crystal of symmetry P2 and of medium hardness. The industry uses it in pigments while gemologists praise its exceptional dispersive power.
This is how the Hollabaugh and Foita resource from the Grisons, Switzerland, appears in the VESTA modeling program – quite an imposing crystal!