Gehlenite.
Description from the source:
Gehlenite ( Ca2 Al (Al Si) O7 tet.), Le Selle, Monzoni, Trento, Italy. Small but evident. 1,5x1x1 cm; 3 g with box. Source:Simone Citon Contributor:John Gray Acquired:14 October, 2008 Text Updated:14 October, 2008 Price: Trade Size: 0.6" Composition:Ca2Al(AlSi)O7