Prehnite with Rutilate 4mm Round - 15-16 Inch July Rocky Butte Jasper strands are

Rocky Butte Jasper strands are predominantly shades of gray

Shungite has been used as a folk medical treatment since the early 18th century

A Manganese inosilicate (or chain silicate)

Rhodonite belongs to the Pyroxenoid group of minerals

Madagascar

Prehnite with Rutilate 4mm Round - 15-16 Inch July Rocky Butte Jasper strands arePrehnite was the first mineral to be named after a person: its discoverer, Dutch Colonel Hendrik Von Prehn. Von Prehn discovered the stone in South Africa in 1774. Prehnite is translucent to transparent, in colors from light green to yellow green to olive, with occasional inclusions of Black Tourmaline that crisscross the stone in fibrous patterns. It is a phyllosilicate composed of silicon, calcium and aluminum with trace amounts of iron.