Often very attractive, inclusions are other minerals captured by the growing quartz crystal     Index to Quartz Digging Cleaning Worth Fee Pay Mines Types Forms Inclusions Geology Mineralogy Synthetic Gemstones Handedness Experiments

Other minerals in Quartz Crystal Inclusions of other minerals in rock crystal and smoky quartz are not particularly uncommon and are often highly attractive. They may be of two general types: early formed minerals that were captured by later formed quartz as it grew and minerals that were forming in or floating in the hydrothermal fluids that were deposited on the growing quartz crystal. Examples of the first type include rutile, actinolite, hedenbergite, some hematite, and tourmaline crystals that formed early and had rock crystal deposited on it, thereby encasing the early minerals. The latter type includes chlorite, cookeite, hematite, mica, pyrite, galena, adularia, and many others, that were deposited as the quartz was crystallizing. In some specific instances, such as asteriated quartz, rutile is thought to have been in solid solution in the quartz and, upon cooling, the rutile was forced out of the quartz structure, resulting in microscopic highly oriented needles. The light, playing off these oriented needles, presents a six-ray star typical of asterism. The various types of included crystals give rise to a variety of lapidary materials and uses. Major sources for these types of gem materials are located in Brazil and Africa.   Contact the authors Rockhounding Arkansas revised July 1998 ©Rockhounding Arkansas 1998 http://rockhoundingAR.com