Garnets are a group of silicate minerals, Garnet forms when a sedimentary rock with high aluminium content, such as shale, is metamorphosed. Garnet has a hardness of 6.5 to 7.5 on the Mohs scale. This piece of Pink Garnet rough from Tanga, Tanzania weighs 8.99 cts, measures 7x10x8mm and has a small veil.