Bloodstone is a mineral with a hardness of 7 out of 10 on the Mohs scale of mineral hardness [?]. These Trigonally structured gems are made of silicon dioxide, their full chemical compound being SiO2.
Bloodstone is a member of the Chalcedony group. Why is it called Bloodstone? Well because in polished and rough form this gem / mineral looks like blood, on a stone. (see photo)
Bloodstone is sometimes referred to as Plasma or Heliotrope. Heliotrope is a birthstone for March. The name plasma is used to define a bloodstone with yellow inclusions, and not red ones.
Despite its relative hardness (7 out of 10 on the Mohs scale), this mineral is usually polished and not cut.
Typical bloodstone is dark green with red inclusions, but as stated earlier it is sometimes dark green with yellow inclusions.
Native Americans used Chalcedony in ceremonies. Chalcedony has also been used to create seals as far back as the bronze age.
It is sometimes used in the manufacturing of electronic devices.