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) Guadaloupe, and his suite. On 30 July, "Amethyst" and two other frigates, and , sailed from Plymouth for the Isle of wight. There they were to pick up Dutch troops that they were to return to Holland. On 10 September "Amethyst" captured the French lugger "Alert", and recaptured a ship. In October 1801 Captain Charles Taylor took command of "Amethyst", only to be replaced in the next month by Captain Henry Glynn, for the North Sea. During the Peace of Amiens, "Amethyst" sailed on anti-smuggling patrols off the coast of Scotland under the command of Captain Alexander Campbell. During the