Amethyst and it can not be differentiated with absolute certainty without advanced gemmological testing (which is often cost-prohibitive). There is one test based on "Brazil law twinning" (a form of quartz twinning where right and left hand quartz structures are combined in a single crystal) which can be used to identify synthetic amethyst rather easily. It is possible to synthesize twinned amethyst, but this type is not available in large quantities in the market. Single-crystal quartz is very desirable in the industry, particularly for keeping the regular vibrations necessary for quartz movements in watches and clocks, which is where a lot
Yangtse Incident: The Story of H.M.S. Amethyst le Yangtse" (French) and "Vuur op de Yangtse" (Flemish/Dutch), both meaning ""Fire on the Yangtse"". The film was entered into the 1957 Cannes Film Festival. On 19 April 1949, the Royal Navy sloop HMS "Amethyst" sails up the Yangtze River on her way to Nanking, the Chinese capital, to deliver supplies to the British Embassy. Suddenly, without warning, People's Liberation Army (PLA) shore batteries open fire and after a heavy engagement, "Amethyst" lies grounded in the mud and badly damaged. attempts to tow "Amethyst" off the mud bank, but is herself hit several times and has to depart. A further