Spider jasper

Spider jasperLocale: Mexico Approx dimensions: 4 x 2 x 1. 5" Approx weight: 330g Spider jasper is called a lot of names in the industry, including chrysanthemum, starburst, and fireworks jasper, due to its distinctive radial starburst pattern on a dark chocolate brown and red tinted background. Spider jasper is in fact not a true jasper, but a variety of rhyolite. A lot of jaspers are actually rhyolite! Mineralogically jasper is a variety of chalcedony, which is a

Locale: Mexico

Approx dimensions: 4 x 2 x 1.5"

Approx weight: 330g

Spider jasper is called a lot of names in the industry, including chrysanthemum, starburst, and fireworks jasper, due to its distinctive radial starburst pattern on a dark chocolate-brown and red-tinted background. 

Spider jasper is in fact not a true jasper, but a variety of rhyolite. A lot of jaspers are actually rhyolite! Mineralogically jasper is a variety of chalcedony, which is a form of quartz. Rhyolite is in the family tree, an igneous rock composed of quartz and feldspar. This material would most accurately be named "chrysanthemum rhyolite" but you know I can't pass up a goblin-y name like spider jasper.

The starbursts in the rhyolite are spherulites: minerals composed of dense radial needle-like growth from a point to create a sphere (hence "spher"ulite). Spherulites are typically crystalized feldspar forming within volcanic igneous quartz-based rock. They commonly appear as distinct circles with banding as in the case of leopardskin jasper. With spider jasper, the spherulites are loose collections of thick needles resembling a firework.

This is one of my favorite spider jasper pieces. The pattern on it looks like a swirling galaxy, exhibiting the flow of the igneous rhyolite. On the duller face, the starburst inclusions appear to have eroded or dissolved out of the rock creating an interesting inverted effect.

Add the rough piece to your collection, drier terrariums, or use as an accent in a succulent bowl. Chunks of rough like this are commonly sold for lapidary purposes, to be polished into tumbles, slabs, carvings, or jewelry. The rough material is already quite beautiful, but colors deepen if polished; images labeled 'wet' preview what to expect if you do wish to polish.