Size  7cm x 5cm
 
A block of black basalt hosts a cavity, 4cm long by 1.5cm high, which is lined with white chabazite crystals. Growing on top of the chabazite are clusters of white natrolite crystals, these are not obvious in the photos, but one can just make them out as larger clumps of crystals on the smaller chabazites.
From a old quarry near Ben Lomond, collected about 25 years ago by Glyn and maxine Francis.