Dumortierite is a rare, blue to violet aluminum borosilicate mineral, often found in metamorphic rocks. It is typically known for its deep blue color, but can also appear in shades of purple, brown, or reddish-brown depending on its mineral content. Dumortierite has a Mohs hardness of 7 to 8, making it relatively durable and suitable for jewelry, particularly as a cabochon or gemstone. It is found in various locations, including Brazil, Madagascar, and the United States. This mineral is valued for its striking color and its ability to take a good polish, making it popular in decorative uses as well.