Aragonite and calcite with pocket of calcite rhombs Chalcedony nodules 25 x 1 x 1"

25 x 1 x 1"

I've found White Sharks to be a bit antisocial

The starbursts in the rhyolite are spherulites: minerals composed of dense radial needle-like growth from a point to create a sphere (hence "spher"ulite)

This flat polished slab of picture sandstone is made from Arizona Sierra sandstone sourced from central Arizona

but overall reaction is poor

Aragonite and calcite with pocket of calcite rhombs Chalcedony nodules 25 x 1 x 1"Locale: Sidi Ayed, Fs Mekns Region, Morocco Approx dimensions: 3. 5 x 2 x 2" Approx size: 425g (0. 9 lb) Calcite and aragonite are polymorphs of one another, meaning that the same chemical composition (calcium carbonate) has crystallized into different crystal structures (trigonal and orthorhombic, respectively). Calcite and aragonite often grow together, and the two minerals are also frequent paramorphs of one anothera pseudomorph of the same