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) of York to the Netherlands and later participated in the evacuation of the force following the campaign's collapse. On 18 December she and recaptured the brig "Jenny". Eleven days after that, "Amethyst" and "Beaulieu" recaptured the ships "Dauphin", "Cato", "Cabrus", and "Nymphe". On 29 December "Amethyst" captured the French privateer brig "Aventurier" (or "Avanture"). "Aventurier", out of Lorient, was armed with 14 guns and had a crew of 75 men. One month earlier, on 29 November, "Aventurier" had captured the American ship "Cato" and taken her master, John Parker, and his crew prisoner. When "Amethyst" captured "Aventurier" Cooke freed the