1.6" Gemmy Heulandite Crystals on Mordenite - Maharashtra, India
This gorgeous, 1.6" wide specimen features gemmy, yellow to colorless heulandite crystals protruding outward from the white mordenite encrusted matrix. It is a relatively new find out of the Deccan Traps (the world largest basalt flow) in Maharashtra, India. These lustrous heulandite crystals contrast nicely against the powdery-white mordenite.
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.