Crystals of aquamarine, a transparent blue variety of beryl (beryllium aluminium sillicate), embedded in kaolin (china clay). Beryl occurs in many colours including grayish-white, yellowish-white, pale bluish-green and, more rarely, transparent yellow (heliodor), pink (morganite), blue (aquamarine) and green (emerald). The rare, transparent varieties are used as gemstones, while the more common types form the principal ore of the metal beryllium. Kaolin is mined for use in the ceramics industry and as a filler in the manufacture of rubber, paper, paint & textiles. This specimen measures 7 x 7 cm and was found in Mimoso do Sul, Brazil.