I have a sample of calcite crystal from Corop in Victoria, Australia. It has a collection of "growths" which I struggle to understand. Given these rocks are Cambrian and were formed in very hot conditions (volcanic, underwater ) no fossils could be expected. It's more likely to be a mineral dissolution feature, but not possible to tell. My problem is the way the "worm holes" butt against each other without joining, suggesting some kind of organic replacement. My mystery appears to follow fractures and isn't evenly tubular. It comes from a road metal quarry in the vicinity of a fault region filled with minerals, where the calcite is among material blasted from a vertical wall so the depth and surrounding rock is not clear. Perhaps it has joined the site over the eons since the rock formed. My local museum geology department has no answer yet. Photographs taken with microscope X10. Any ideas?