Rock Review: Mushroom Jasper

Today’s gemstone, Mushroom Jasper, is a wonderful choice for those looking to add a unique piece to their jewelry collection.

Geology Buzz

When Mushroom Jasper was first discovered, it had some identity confusion. Because it was found near a deposit of Quartzite in Arizona, it was first thought to be a variety of Quartzite. Once it was determined not to be that gemstone, it was then termed a “Jasper”. Although the “Jasper” name has stuck, we now know it to be type of highly silicated Rhyolite (volcanic rock) with unusual circular formations that resemble mushrooms. Mushroom Jaspers are often seen with a brick red background that bears orbital patterns in a range of grays and browns.

Mushroom Jaspers open are found as “thunder eggs” geode like rock balls that are plain looking on the outside, but contain gemstone on the inner layers. These freeform rocks can then be cut and shaped into lovely cabochons, since they are able to take a high polish.

Fun Facts

If you’re an animal lover, Rhyolite is the stone for you. All Rhyolites are thought to strengthen bonds between animals and humans, especially children. It is believed to be particularly effective for use with cats, since it’s often found in environments that are well suited to wild cats.

In prehistoric times, the largest beds of Rhyolite existed in Eastern Pennsylvania, our studio’s own backyard! Today, there is still lots of Rhyolite to be found just under the earth’s surface in Pennsylvania in Adams, Cumberland, Franklin, Chester, Delaware and Lancaster counties.