A mottled gemstone of Chromium Lawsonite from Syros island, Greece.

Lawsonite is a rare variant of the Feldspar mineral Anorthite named for the American professor of Geology Andrew Cowper Lawson.
It is a hydrous calcium aluminium silicate, in this case a chromium-bearing sub-variant with chemical formula Ca(Al,Cr)₂[Si₂O₇](OH)₂ · H₂O.
Its Chromium content is responsible for the green colour seen in this gem.

weight:  2.56 carats
shape:   Fancy kite shape cut
dimensions:   11.01 x 10.98 x 5.36 mm
treatment:  None