Apatiteis a mineral the name of which is of Greek origin. It is usually translucent and can be found in green-blue. It often displays a red iridescence and the star effect, known as asterism. It has a hardness of 5 and a specific gravity of 3.2. Due to its low hardness it is brittle and is not often used in the jewelry industry.
Lava is the molten substance released by volcanoes and is an Italian word meaning ‘flooding’. The Earth’s crust is largely made up of solidified lava. Lava is often used to make jewelry. In fact, lava and gagate jewelry were also fashionable in the 19th century during the so-called Victorian period.
Hematite is an opaque mineral consisting of iron oxides. Its name is of Greek origin, and is due to the color of the powder encountered during processing, which is red like blood (αίμα – hema, into Greek). It exhibits a metallic luster, and its color is steel gray, gray to black. Its hardness is 6.5 and its specific gravity is 5.05. It has been used for making jewelry since 3000 BC.