Amethyst – Natural, Specimen, Purple

Sometimes during a crystal's formation, a new layer grows over a transparent crystal. When the growth of the original crystal resumes, it's left covered with a "shroud." These inclusions of now indistinct, almost transparent crystals are called phantoms. This amethyst specimen contains pyramidal phantoms. La Sirena Mine, Mun. de Guanajuato, Guanajuato, Mexico. © Rob Lavinsky, www.iRocks.com. Used with permission.

Article: Descriptive Crystallography for Gemologists

Credit: www.iRocks.com