Galena in the eye cosmetic kohl. In Ancient Egypt, this was applied around the eyes to reduce the glare of the desert sun and to repel flies, which were a potential source of disease. galena is the primary ore of lead, which is mainly used in making lead–acid batteries; however, significant amounts are also used to make lead sheeting and lead shot. Galena is often mined for its silver content, such as at the Galena Mine in northern Idaho. It is also used in pencils in the older times. Also known as "potter's ore", galena is used in a green glaze
Mineral ore of zinc, or cassiterite (SnO), an ore of tin. Gems are minerals with an ornamental value, and are distinguished from non-gems by their beauty, durability, and usually, rarity. There are about 20 mineral species that qualify as gem minerals, which constitute about 35 of the most common gemstones. Gem minerals are often present in several varieties, and so one mineral can account for several different gemstones; for example, ruby and sapphire are both corundum, AlO. Minerals are classified by variety, species, series and group, in order of increasing generality. The basic level of definition is that of mineral species,