Onyx is a variety of agate encountered in white, black and beige-brown. Its name is of Greek origin and refers to the lines that can be seen on the claws of several animals. It is considered to give courage to overcome difficulties and encourage decision-making. This mineral is also mentioned in Theophrastus’ work. In the bible, it represents Benjamin, the twelfth tribe of Israel.
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.