Barite, the primary ore of barium, is a high density mineral with a wide range of industrial uses. It occurs mainly as clusters of tabular crystals or white bladed masses. Barite has high specific gravity that cause it to be very heavy for a non-metallic mineral, making it easy to identify in comparison with similar-looking specimens of quartz, calcite or gypsum. Due to its high density barite can block gamma-rays and x-rays.
Chemical composition: BaSO4; Hardness: 3
Fluorite is a common mineral that is deposited in veins during hydrothermal processes. It comes in a rainbow of colors, can have a vitreous or dull lustre and sometimes exhibits fluorescence. Fluorite has four directions of perfect cleavage and can often be found in octahedron shapes.
Chemical composition: CaF2; Hardness: 4