Kyanite is an attractive mineral that has a near sapphire like blue color in some especially nice specimens, but also can be white, gray or green. kyanite's ability to quiet the mind is virtually unequaled. It...
Amethyst is the purple variety of quartz. Its chemical formula is SiO2. Amethyst's coloration is due to a complex interplay of iron and aluminium. Amethyst is the birthstone of February. It has been believed...
Chalcedony has a waxy lustre, and may be semitransparent or translucent. Its chemical formula is also SiO2, same as quartz. But quartz has a triangular crystal structure, whiles chalcedony is monoclinic....