Malachite 12-17x16-21mm A Grade Small Free Form Cabochon Stone Type_Dendritic Agate These gauges are often used

These gauges are often used to display dimensional information in science & engineering but is convenient for creative use as well

Wood Opalite occurs in a range of colors

if desired

an opaque silicon dioxide mineral and form of microcrystalline Chalcedony

Black Silverleaf Jasper is a rare form of Jasper

Malachite 12-17x16-21mm A Grade Small Free Form Cabochon Stone Type_Dendritic Agate These gauges are often usedMalachite is a copper carbonate with a bright green color and dark green banding. Usually found near copper deposits, it is formed through the combination of carbonated water, limestone and copper. Famous malachite mines in the Ural mountains of Russia once produced 20 to ton blocks of the stone, while today it is primarily mined in Africa. Malachite was used extensively as decoration in the palaces of Russian tsars and forms the columns of St. Isaacs