The Trapiche Growth Phenomenon

There are various interpretations on the trapiche growth phenomena in colored stones. In the past experts got confused with the unusual growth pattern to twinning. The unusual growth pattern is usually visible in beryl, variety emerald, (Muzo, La Pena, Coscuez) and corundum, variety ruby and sapphire (Burma(Mong Hsu) and Vietnam). One theory is that the phenomenon in beryl and corundum are due to skeletal or dendritic growth, where edges and corners tend to grow much faster than the faces of a crystal. Another interpretation on the phenomenon in trapiche rubies and sapphires from Burma and Vietnam are due to skeletal growth followed by layer-by-layer growth. To make a long story short, rapid growth and changes in the growth conditions are believed to be the origin of the unusual patterns in beryl and corundum. The trapiche phenomenon is also seen in andalusite, tourmaline, and quartz. For now there are no nomenclatures for fixed star patterns that are being offered as trapiche in the gem market.