Glintstone Cluster

{t}: Add {u} or {r}. Spend this mana only to cast
instant or sorcery spells, or to activate the abilities
of creatures.
Sacrifice Glintstone Scrap: Scry 2, then draw X
cards, where X is the number of instant and
sorcery spells you cast this turn.

Glintstone is believed to be the crystallized remnant of
stars fallen to earth. Thus the stars' fates for us may
be read within its sparkling depths.