Aragonite and calcite with botryoidal side Geode This piece is covered with

This piece is covered with around two dozen hydroxyapophyllite crystals

Daylight fluorescence means the material reacts to the UV in sunlight

I have a hard time passing up isopod morphs with mineral names

Approx weight: 228g

Chalcedony is the cryptocrystalline version of quartz with similar requirements for growth

Aragonite and calcite with botryoidal side Geode This piece is covered withLocale: Sidi Ayed, Fs Mekns Region, Morocco Approx dimensions: 3 x 2. 75 x 2" Approx size: 480g (1 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 chemical