“Scolecite crystal of ~ 0.25 mm diameter in transmitted polarised light, crossed polars. The upper picture indicates due to several interference colours that it is not homogenous, rather a bundle of several crystals or twinned. It is also not qenched if parallel to the polarisation direction, which natrolite would do. The lower picture shows quenching at about 15° for the upper half, which indicates twinning. Natrolite and mesolite can be excluded. Terminations on the crystals are not visible. The paragenesis is heulandite. So the overall conclusion is scolecite. ”

“Cluster of scolecite crystals with some heulandite. Collected from a ravine a few m above the road. Most of the rock there is now covered with rockfall nets. ”