Afghanite is a rare Feldspathoid mineral. In essence, it’s a complex aluminosilicate that happened because Feldspar couldn’t (because there wasn’t enough silica for Feldspar).
These are extremely unusual to find with good distinction of form (you can see the faces), and good crystal isolation. Specimens that pass light when exposed are highly prized among collectors.
This specimen is from the type locality (the place it was discovered) for Afghanite, but notably, all other localities for Afghanite either are micro minerals, or smears of blue on an conglomerate of rock thing.
5.2 x 5.2 x 3 cm.