Twinning Many of the crystals with the strongest adularescence also show unusual crystal forms, and experts on twinning are invited to look at the material. Study material is available from this author. Physical structure not fully determined Investigators with access to SEM and TEM and other equipment capable of defining the periodicity and spacing of the the polysynthetic twins are needed. Study material is available to qualified researchers at no cost Observations of Uruguayan amethyst and colorless quartz showing adularescence. Three photos of a Uruguayan amethyst crystal.
Optical phenomenon is found in colorless zone on outer portion of crystal.
Photos by John Koivula, Gemological Institute of America. Relatively minor in relation to total specimens produced by Uruguayan mining Companies. It appears as a sheet of light extending from beneath the minor rhom. When the xls are not heavily etched at the rhom. Usually the color is whitish.