7.4" Red Cap Amethyst Crystal - Thunder Bay, Ontario

In the 1950's amethyst deposits were discovered about 30 miles NE of Thunder Bay Ontario while building a road. Since the 1960's it has been mined in the area. The amethyst from Thunder Bay can range from light, delicate purples to almost black in color. One very distinctive characteristics of many Thunder Bay amethyst crystals is the the inclusion of red hematite (microscopic disks/spherules within the amethyst). These inclusions can cause crystals to have red highlights, zones or even appear completely red in color.

Amethyst is a purple variety of quartz (SiO2) and owes its violet color to natural irradiation, iron impurities, and the presence of trace elements, which result in complex crystal lattice substitutions. It’s considered a semi-precious gemstone, and just two centuries ago was considered to have a value on par with diamonds, sapphires and rubies. The largest and best known amethyst deposits occur in southern Brazil and Uruguay but many localities around the world produce an amazing variety of amethyst crystals and formations.

Silicon Dioxide, also known as SiO2 or Quartz, is the second most abundant mineral in the Earth's crust. Quartz crystals generally grow in silica-rich, hot watery solutions called hydrothermal environments, at temperatures between 100°C and 450°C, and usually under very high pressure. Quartz veins are formed when open fissures are filled with hot water during the closing stages of mountains forming, and can be hundreds of millions of years old.