Apophyllite and Stilbite

Sample of greenish/transparent euhedral tabular Apophyllite crystals entwined with white "wheat sheaves" of Stilbite. Apophyllite crystals have a pearly lustre and Stilbite crystals have a pearly and vitreous lustre. Average Apophyllite crystal size: 1.8 cm x 0.6 cm x 0.5 cm. Largest Stilbite crystal size: 1.0 cm x 1.5 cm x 0.7 cm. Apophyllite (KCa4Si8O20(F,OH) x 8H2O) can be colourless, white, grey, greenish, yellowish or reddish in colour. Lustre is vitreous and pearly on the cleavage. Streak is white and hardness is 4 1/2 to 5. Cleavage is perfect in one direction. Apophyllite can occur as cube-like or tabular with a square cross section but can also be lamellar, granular or compact. Stilbite (NaCa2Al5Si13O36 x 16H2O) can be white, greyish, yellowish, red or brown. Lustre is vitreous and pearly on the cleavage. Steak is colourless and hardness is 3 1/2 to 4. Cleavage is perfect in one direction. Stilbite usually occurs as bladed aggregates that appear as "wheat sheaves" but can also be radial, globular, or tabular crystals (rare).