Growth Interference Quartz (GIQ) is an occurrence where Quartz and Calcite compete for space in solution. The calcite changes the habit of the quartz by interfering with the normal quartz growth. When the calcite is then etched away with acid, the results are some fantastic and wild shapes and habits of Quartz!! In 2007 we bought the largest existing lot of Bor Quarry Quartz with Growth Interference from Dalnegorsk. Here you will find a full spectrum of GIQ plus other oddball Quartzes from the Bor Quarry.