Definition Day: Agate Vs. Jasper

If you love working with semi-precious beads but falter when someones starts asking if something is an agate or a jasper, I've found the resource you've been looking for.

Dakota Stones provides a concise explanation that may not make you an instant gemologist, but will certainly add to your own knowledge base.  I'm sharing their article here, and you can click on the photo at right or the name highlighted above to go to their site.  With thanks (and all the credit) to Dakota Stones, keep reading.

How to tell the difference between Jasper and an Agate?  The simple answer is if you put light behind the material and you can see through it, then it is an Agate; if you can’t, then you’re holding Jasper.  

Agate

The more complex answer is that it is not always that straightforward. The simple science behind this question is that both Agates and Jaspers are comprised of Quartz—which is one of the most common minerals on the planet. Quartz is comprised of two major types—macrocrystalline (large crystal) and cryptocrystalline (small crystal).

Botswana agate

Now here is where it can get confusing.  One major variety of cryptocrystalline quartz is Chalcedony.  Chalcedony includes Carnelian, Chrysophase, Agate, Bloodstone, Jasper and others. When Chalcedony in concentrically banded it is called an Agate. Occasionally the banding is larger than the crystal and the banding is not visible—like with most Carnelian.

Carnelian

Another sub-variety of Chalcedony is opaque quartz called Jasper.  Jasper can be banded or striated, depending on how it formed, and are most commonly red, yellow, green, brown or a mixture of these colors.

Peacock jasper

Examples of Macrocrystalline Quartz are clear quartz, Smokey Quartz, Amethyst, and Citrine, which forms in a singular point or clusters. But these are neither Agates nor Jaspers, so we’re moving on from these.

Smoky quartz

The main reason it is difficult to differentiate an Agate from Jasper is that they originate from the same minerals. Another major reason is due to the mislabeling of materials being cut in foreign countries as either an Agate or Jasper without considering the science in the naming process.  We recognize this problem quite often, but for reasons of consistency in the marketplace we use the incorrect label.

Porcelain jasper

I hope this sheds a little light on the differences between Jasper and Agate and provides you with a quick test to tell the difference for yourself, even if it is labeled otherwise. 

Red creek jasper

Blue lace agate

Dragon blood jasper

Tree agate