Tanzanite Museum Arusha, Tanzanite is one of the rarest gems in the world, and it can only be found in Tanzania. When you go to the Tanzanite Museum Arusha, you should if you like shiny stones. There is a fake mine shaft where you can see and touch this lovely violet-blue gemstone and learn all about how it is found, cut, and handled. You can even buy your own example to take home.