Like chabazite, the zeolite stilbite is common as a fine-grained constituent of  low-grade meta-basic rocks and greywackes, but also occurs as much coarser crystals in veins and amygdules in the similar rocks.  Stilbite has low to moderate negative relief relative to quartz or albite with which it may be associated.  In image A the relief of stilbite is similar to that of epoxy filling a small hole (which also contains an air bubble) in the upper left.  In amygdules it typically occurs in sheaves or bundles of crystals (B).  Stilbite is colourless in plane polarized light (A) and has maximum interference colours of first order white and parallel extinction.  Sample from unknown location.  Fields of view are 5.5 mm across.  A ppl, B x-nicols.