Apophyllite, a Zeolite, is Silicate mineral with very well defined clear Crystals and is very popular as a collector’s mineral. The Crystal structure will refract like in obvious rainbows and can form “natural pyramids” when tumbled.
Stilbite is another Silicate mineral from the Zeolite family. It is often characterized by its sheaf like aggregates. The color is usually white or pink and when the cleavage is perfect, will have a distinct pearly luster.
Heulandite is a mineral series from the Zeolite group. The Crystals have a coffin-shaped habit but may also form simple rhombic prisms. The mineral is usually colorless or white but may have orange, brown, yellow, brick-red or green inclusions due to a Celadonite content.