#iron silicate

• Almandine — A silicate mineral representing the most widespread and common species of the garnet group, featuring a characteristic deep red, purplish-red, reddish-brown, or black color, containing iron and aluminum. It crystallizes in the cubic system, has a vitreous luster, and high hardness (7-7.5 on the Mohs scale), with its transparent varieties utilized since antiquity as semi-precious gemstones in jewelry and opaque ones as industrial abrasives.
• Andradite — A mineral belonging to the silicate group and the garnet subgroup, chemically composed of calcium iron silicate. This structural mineral occurs in metamorphic rocks (especially skarns and crystalline limestones) and crystallizes in dodecahedral or trapezohedral forms with shades of yellow, green, brown, or black, being highly valued in its rare varieties (such as demantoid and melanite) as a gemstone.