Prehnite is a hydrated calcium aluminum silicate. Prehnite comes in a nice medium apple green and progresses down to a light greenish yellow. It may also be a brownish yellow. Prehnite is fairley durable having a hardness of 6 to 6.5. Prehnite may have a luminous quality, as it's luster is vitreous to pearly. Originally found in south Africa, Prehnite is now found several other locations. such as USA, Australia and China. This specien has 2 or 3 different colors of green. The specimen is tryangle shape hence the three pictures. This specimen comes from Southbury Connecticut.