Fluorite & Barite

Fluorite – CaF2
Elements: Calcium, Fluorine
Class: Halides
Crystal System: Cubic
Hardness: 4
Fluorite
Talc (1)Diamond (10)
Softer than glass. A steel knife scratches it.
Barite – BaSO4
Elements: Barium, Sulfur, Oxygen
Class: Sulfates – Sulfates
Crystal System: Orthorhombic
Hardness: 3-3.5
Calcite
Talc (1)Diamond (10)
A copper coin can scratch it.
Origin: Berbes, Ribadesella, Asturias – Spain
Did you know?

Fluorite gave fluorescence its name. In 1852 the physicist George Stokes, studying the mineral's glow under invisible light, coined the word for the whole phenomenon after the stone itself.

Barite feels surprisingly heavy for a pale crystal, the weight of its barium. Around 1603 a Bologna shoemaker roasted some and found it glowed in the dark, the Bologna stone, the first artificial phosphor ever made.