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
HMS Amethyst (1799) Frigate, at the Action of 6 April 1809. "Niémen" had 47 killed and 73 wounded; "Amethyst" had eight killed and 37 wounded. In 1847 the Admiralty authorized the issue of the Naval General Service Medal with clasp "Amethyst 5 April 1809". Later in the year, Seymour participated in the Walcheren Expedition, providing naval support to the transports. On 11 August she was part of a squadron under Captain William Stewart that forced the passage between shore batteries at Flushing and Cadsand. "Amethyst" had one man killed and one man wounded in the operation. Seymour left the ship in 1809; his