Agate Month

Happy Agate

An agate slab with a happy smiley face in its brown bands.

Smiley face agate photo by Cobalt123 from https://flic.kr/p/dVdpEA

An agate dressed up for Halloween, hanging out at the Tucson Rock and Gem Show 2013.  Thanks for following us all the way through Agate Month and learning all about these beautiful minerals!
If you’d like to see a list of even more types of agates, go here: http://stoneplus.cst.cmich.edu/agate.htm

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Shadow Agate

Shadow agates are hard to photograph, because it’s more of an effect. When you move shadow agates back and forth, you can see deep, dark areas that appear to move. They look like they are deep inside the stone.

Flame and Frost Agates

These aren’t technically types of agate according to Mindat, but sometimes they will be described this way in rock shops or on rockhound websites.  And these pictures are so great I couldn’t possibly pass them up.  An agate with red, orange, or yellow plumes in just the right arangement can be called a flame agate, because it looks like fire.

Red, orange, and yellow plumes shooting up from a white and transparent agate matrix, looking like flames.

Photo by Vítězslav Snášel from http://www.mindat.org/photo-114774.html

Frost agate describes the cracked finish on these beads (again, it’s not a mineralogical term).  They can also be called cracked agate.  The frost effect is heightened when they are blue. Whatever they are, I would totally wear earrings made with these beads.

Cloud Agates

Cloud agates look like they contain clouds. They can have a gray or transparent matrix and the inclusions are usually white and foggy to look like clouds.  The one on the left has a bit of a drusy effect which makes it look like a puffy cumulus cloud.  The cloud agate on the right has a blue “cloud” inside.  The North Lincoln Agate Society has given its friend some googly eyes.

Chinese Rain Flower Agates

Chinese rain flower agates are found in Nanijing, China in the bed of the Yangtze River.  They can also be called Yuhashi or Yuhua stones.  The river polishes them smooth, and people often display them in a small bowl of water to bring out the colors.  They look very similar to Lake Superior agates, and like Lake Superior agates, they are named after where they came from.

Landscape Agates

A landscape agate is any agate with inclusions that appear to be a landscape scene.  This usually includes plumes or dendrites, because they look so much like trees. I was unable to find the original sources for some of these cabochons, but I think the beautiful photos speak for themselves.  Which one is your favorite?

Enhydro Agates

A blue-gray polished agate with circular swirls.  You can't see it, but there is water inside.

Photo by Verity Woolf, from collection of Jo Woolf.  Retrieved from: http://the-hazel-tree.com/2014/01/06/enhydro-agate-a-secret-water-chamber/

Sometimes, agates will have a little bubble of water trapped inside.  This is called an enhydro.  The water inside is millions of years old!  The water can be seen if you shine a light on the agate from behind, or heard if you shake it.  Eventually, the water will work its way out and evaporate via small capillaries, but the hollow part will still remain.  It is also possible that water could enter the agate through the same capillaries.  Enhydros can be found in watery places where agates are found, such as Brazil, Indonesia, and Oregon.  Photos don’t show this very well, but on the link in the photo, the owner has some videos that show off the water inside.

For more information about enhydros, go here: http://www.rocksinmyheadtoo.com/Enhydros.htm

Agates and Jasper

Jasper and agates are both a type of quartz known as chalcedony. So it makes perfect sense that sometimes you can find jasper and agate melded together, like so. Agates are usually transparent or translucent, and jasper is usually opaque, but this isn’t a hard and fast rule. Sometimes it’s very difficult to tell the difference between agate and jasper, in which case people may call it chalcedony, agate jasper, or jaspagate. It is mostly found in the American Southwest and California, like other agates and chalcedonies. The one pictured was found near the San Andreas Fault.

Thunder Eggs

The thunder egg was declared the official state rock of Oregon in 1965, because there are quite a lot of them there. A thunder egg is a rounded nodule or geode with agate in the center.  Thunder eggs can also contain quartz, chalcedony, crystals, or opal.  The inside parts can be opaque or transparent – there are almost as many possible designs as there are agates.  This unusual thunder egg shown above is from Oregon and has plume inclusions. Some thunder eggs are also geodes but this one is not a geode because it does not have crystal points. A more typical thunder egg would look similar, but with bands or a single color on the inner part.