This is the eighth in a series on the gemstones of Namibia. Dispersion is a measure of a gem’s property of separating light into its constituent colours, as a prism does, and is frequently referred to as the ‘fire’ of the gem. Demantoid ranks high among gemstones for dispersion; in fact, even higher than a diamond.

This is the ninth in a series about Namibian gemstones. Specific Gravity (SG) is a measure of the relative density of a gem, which varies in its chemical composition and crystal construction. By comparing the weight of the gem in air with its weight suspended in water, an SG value is established. Specific Gravity values are useful in identifying an unknown gem, or in determining the size of a new gem to be fitted into an old setting.

This is the tenth in a series about Namibian gemstones. Brittleness is one factor to be considered when buying and mounting a gem; it is not uncommon for a relatively hard stone to be brittle, particularly along facet cuts. To minimise damage, brittle stones are frequently used for necklace beads, pendants, or small ornamental sculptures. A relatively brittle stone, rose quartz has been cherished as a symbol of romantic love through the ages, and polished stones shaped like a heart are commonly presented as gifts to loved ones