The name “Jasper” is a generic name given to any spotted or multicolored stone. It comes from the French word jaspre, which literally means “spotted or speckled stone” Some Jaspers are “true Jaspers,” meaning they are an opaque variety of spotted Chalcedony, like Brecciated Jasper. However, monochromatic chalcedony is often sold using the name Jasper, such as Red Jasper or Yellow Jasper, as is multicolored chalcedony without spots, like Desert Jasper and Mookaite Jasper. The name Jasper is also given to a variety of spotted rocks, most often a form of Rhyolite, examples include Leopardskin Jasper, Ocean Jasper and Rainforest Jasper. Because so many different types of stones may be referred to as a Jasper, it is difficult to know exactly which stone is being referenced in ancient and medieval writings.
Red Jasper has long been credited for its supposed ability to stop hemorrhages and reduce pulse rate. In 1636, the Gemmarum et Lapidum Historia described how a young woman was cured from chronic hemorrhaging by wearing Red Jasper. During the Middle Ages, Red Jasper was also considered a stone for warriors and was said to increase their strength and courage. According to legend, a piece of Red Jasper was set on the hilt of ‘Balmung,’ the legendary sword of the Norse hero Siegfried which he used to kill a dragon.
Desert Jasper is one of the newer varieties, discovered in 2006 along the dry Northwestern coast of Madagascar, while prospectors were searching for more deposits of the famously colorful Ocean Jasper. While both varieties of Jaspers have bright colors, Desert Jasper lacks the orbicular spots that make Ocean Jasper so distinctive. Desert Jasper is a variety of Polychrome Jasper, which means “painted with many colors.” Polychrome Jasper is found in several locations worldwide, with each deposit having a very distinct coloring and character. The variety found in Madagascar is notable for its desert-hues and strong contrasting colors. Northwestern Madagascar is primarily composed of sedimentary rocks and most likely Desert Jasper is a combination of minerals and limestone that have been silicified, in a similar fashion to that of Mookaite Jasper in Australia.