1.8" Red-Orange Heulandite Crystal Cluster - Maharashtra, India

Heulandite is a mineral of the zeolite group that also fits within the silicate and tectosilicates groups. It has the general chemical formula (Ca,Na)2-3Al3(Al,Si)2Si13O36 · 12H2O, however the calcium and sodium can be subsituted by potassium, barium and strontium ions. Heulandite crystals will often form as distinctive tabular, radiating crystals with a vitreous luster, of which can display a variety of colors including white, green, brown, orange, red, pink, yellow, grey and black.