Amethyst is not primarily defined by carat weight; this is different to most gemstones where the carat weight exponentially increases the value of the stone. The biggest factor in the value of amethyst is the color displayed. The highest grade amethyst (called "Deep Russian") is exceptionally rare and therefore, when one is found, its value is dependent on the demand of collectors. It is, however, still orders of magnitude lower than the highest grade sapphires or rubies (padparadscha sapphire or "pigeon's blood" ruby). Amethyst Amethyst is a violet variety of quartz. The name comes from the Koine Greek ἀμέθυστος "amethystos" from
Yangtse Incident: The Story of H.M.S. Amethyst rescue attempt by two other ships also comes under heavy fire and has to be aborted. Fifty-four of "Amethyst"s crew are dead, dying or seriously wounded, while others deteriorate from the tropical heat and the lack of essential medicines, including the ship's captain, who dies of his wounds. An attempt to evacuate the wounded is only partially successful - the officers of the "Amethyst" become aware that two petty officers have been captured by the PLA and are being held at a nearby military hospital. Lieutenant Commander John Kerans (Richard Todd), a naval attaché in nearby Nanking, is ordered to