Gem Profile May 18: Moss Agate and Plume Agate

By on May 18, 2012
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by Rose Marion, Wire-Sculpture.com

Today's Gem Profile is...

Moss Agate and Plume Agate, one in a Series on Quartz

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Just as there are many kinds of included quartz, there are several varieties of included agate. Sagenite agate, or sagenitic agate, has needlelike inclusions in a sunburst or fan shape, and come in a variety of colors. Here’s an example of a neon yellow sagenitic agate! Dendritic agate, such as Montana agate, just like its quartz counterpart, has thin, dark, tree or branchlike inclusions. Plume agate has featherlike inclusions that resemble smoke, clouds, or feathers. Finally, moss agate has the appearance of green moss, seaweed, or blue cheese on a translucent background. Moss agate is the most common and most well-known included agate for jewelry makers.

Frances Lediaev wire wrapped this beautiful moss agate cabochon.

Frances Lediaev wire wrapped this beautiful moss agate cabochon.

Some rockhounds don’t consider these included agate stones to be true agate because they do not have the concentric ¬†typical of most agates banding (banding formed in gradually larger circles that share a center point). However, they are definitely part of the quartz-chalcedony-agate family of silica minerals, formed from silicone dioxide. In fact, Montana agate and Plume agate are among the top tier of agates in jewelry making, surpassed only by rare stones such as fire agate.

Moss Agate

Moss agate is typically a green agate with pale to translucent patches of stone; tree agate shares the green, moss-like inclusions but has white opaque patches, rather than translucence.

moss agate and tree agate cabochons

A moss agate cabochon, left, and tree agate cabochon, right. They are essentially the same (and often both are called moss agate), but tree agate has opaque white patches, whereas moss agate is translucent with the same green, mosslike inclusions.

Judy Copeland wire wrapped this moss agate in silver craft wire

Judy Copeland wire wrapped this moss agate in silver craft wire. The design in the stone looked to Judy like a rainstorm with lighting! It is hung on a base metal Viking weave necklace.

Montana moss agate is unique in that it originally formed in the volcanic region of Yellowstone National Park. Now it can be found in the gravel of the Yellowstone River in Montana, and typically has red (iron oxide) and black (manganese oxide) large inclusions on a translucent background.

Montana moss agate pendant wire wrapped by Judi Hogan

Judi Hogan wire wrapped this Montana Moss agate in an angular cabochon pendant frame.

Plume Agate

Plume agate draws its name from the fluffy, feather-like shapes it exhibits. There are several types of plume agate, including Priday, Graveyard Point, Del Norte, West Texas, and Mexican Plume. This plume agate is from Texas; I have a cab of Texas plume agate that shares the same gold, orange, green, and white colors.

plume agate slabs from Dorothy Duflo

This graveyard point plume agate slab comes from Dorothy Duflo: at left, on a background, and at right, held to the sun. Dorothy's wondering what to do with it: what do you think of a belt buckle?

In Tucson, I saw Graveyard Point Plume Agate for the first time: this distinctive golden, tan, white, and gray-blue (and sometimes pink) agate is named for the stone’s location, found in the Owyhee Mountains along the Idaho-Oregon border, near the burial place of an 18th century massacre.

A tub of graveyard point plume agate slices in Tucson, picture by Rose Marion

I found this tub of graveyard point plume agate slices, ready to be cut into cabs, at the RV Park Show near the TEP Show in Tucson 2012.

wet graveyard point plume agate slices photo by Rose Marion

Here's a closeup of the same graveyard point plume agate slices, sparkling wet in the Arizona sun.

Priday plume agate is another name you may come across, which was a rare plume agate found on the Priday ranch outside Madras, Oregon, round in thunder eggs. However, this agate is practically played out. You can find pictures of beautiful Priday Plume agate stones here.

The Regency Rose variety of plume agate is located near the Graveyard Point area and has the tan hues of that stone as well as reds and pinks.

Regency Rose Plume Agate wire wrapped necklace by Judi Hogan

Regency Rose Plume Agate wire wrapped necklace by Judi Hogan

Next week, I will cover some agate you may have wire wrapped, or seen in person: thundereggs, geodes, and I’ll also touch on crazy lace agate. Have you made wire jewelry with thunderegg agate, geodes, or crazy lace agate? Send your agate pictures to tips@wire-sculpture.com, and they could be featured!

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Gem Profile by Rose Marion

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