Dalmatian Jasper Stone from Mexico
Large Dalmatian Jasper, more correctly known as Dalmatian Stone.
The stone on the left is the only piece now available.
Dalmatian Jasper is a trade name which came about because of the stone's spotted appearance. Ironically, most of the world's supply comes from the state of Chihuahua.
Trade names are widely used to popularise certain rocks and minerals, but they can be misleading about the material's chemical composition.
Tests carried out on Dalmatian Jasper revealed it's an alkali feldspar granite. The correct name for this material is Perthite, after the city of Perth (Ontario, Canada), where it was discovered.
Although often reported to be tourmaline, these distinctive spots are arfvedsonite. This rare mineral was named after the Swedish chemist Johan August Arfwedson, who discovered it.
