Agate vs. Jasper: Here’s the Differences

If you want to tell the difference between agate and jasper, it isn’t as hard as you think.

If you want the simple answer, it’s as easy as shining a light through the crystal you have.  If the light shines through it, then it’s more than likely an agate; however, if you can’t, then it’s more than like a jasper.  This isn’t always the case, though, because what you’re holding may not even be a jasper or agate stone.

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As some of the most common rocks people go rock-hounding for, these tips can hopefully help you distinguish the differences between the two.

In today’s post, let’s explore agate versus jasper stones and how we can separate the two.

Agate vs. Jasper

Agate and jasper are both made up of quartz, which is one of the most common minerals found on our planet.  It’s made up of two major types of minerals, which is macrocrystalline, the larger crystal, and cryptocrystalline, the smaller crystal, which can only be seen with a microscope. This seems simple enough, right?

Not quite.

One major quartz is what’s known as chalcedony, which includes a wide variety of crystals, including chrysoprase, chrysocolla, carnelians, agate, jasper, bloodstone and so many others.  Chalcedony is a generic name given to stones that are composed of microcrystalline quartz.  It’s a durable material, and it’s the main reason so many people are attracted to it.

If chalcedony is banded, then it’s an agate, but if it’s opaque, which means light can’t shine through, then it’s a sub-variety of chalcedony, commonly referred to as a jasper stone.

Both of these rocks are very similar materials wise, and are even formed in the same way.   However, as they are all a type of chalcedony, it’s the patterns, colors and translucency mainly that determine which is which.  Whichever minerals are mixed in during the crystallization process will determine how the stone turns out.  This can take hundreds of thousands of years to form.

Virtually, any color can be noted, but the color, like all minerals, will depend on the mineral content as well as the conditions in which the stone was formed over the many years.  As the rock forms, patterns arise.  It’s hard to determine an agate or jasper just by looking at the color since each can come in almost the same color.  It’s the translucency that will determine what stone you have.

In some cases, they can form together, and if so, it’s referred to as a jasp-agate.

What is agate?

Agate, a form of chalcedony, is mostly translucent in color, which means you can see almost clearly through it when held up to the light.  Even if it’s foggy or distorted, seeing a source of light means it’s an agate stone.  As mentioned in the intro, if you see no light shining through, then it’s not an agate.

Agate is compromised of banded materials, which can be identified by either a microscope or even your eye.  So, if you see a banded material on the stone, there’s a good chance you have an agate.  However, do keep in mind that some agates do not have obvious bands.

Found throughout the world, agates are mainly found where volcanic activities occurred, as this is how agates are formed.  Volcanic activity can produce silica, which, as a volcano erupts, the ashes in the silica will dissolve in rainwater after it rains, turning it into a silica gel.  The gel is then held in the volcano activities, slowly crystalizing over time, usually in layers, forming the stones, as well as the banding, you see today.  It is the water-silica solution that forms the agate, which then results in translucency.  The impurities give the agates their color.

What is jasper?

To make things simple, jasper is almost the opposite of that of agate.  As mentioned, you can’t see through a jasper when it’s held up to a light.  It will have the same structure as an agate, but it looks more like a rock.

Jasper is often banded or marked with long, thin parallel streaks, and this all depends on how it’s formed during the crystallization process.  Most common jasper colors may include brown, yellow, green, red or even a mix of those mentioned.  Like agate, impurities and foreign materials can change the colors.

When silica is dissolved in water and formed into the gel, it’s transparent, but keep in mind that most chalcedony formation takes place in volcanic eruption areas where silica gel was found flowing on the ground.  This gel is able to mix with various minerals, which gives the stone its appearance, and the impurities adds the color.  It is these impurities that creates the structure of the stone, which can block the light from passing through.

As you can see, the crystallization process is very similar, it’s just the impurities that can change the stone’s dynamic.

Don’t confuse these stones

The term “agate” and “jasper” are used quite often on the market and sometimes, it does cause confusion.

For example, the picasso stone, sometimes referred to as a picasso jasper, is not really a jasper because it’s actually a dolomite, which is a carbonate rock very different than that of a quartz.

Also, bumblebee jasper isn’t a jasper or agate stone.  It’s a lithified sediment formed from many volcanic material.  Even though it’s banded and opaque, scientifically it is neither.  Rather, it should be referred to as a bumblebee stone.

Flower, orca and even moss agate are not true agates, either, as they are not banded, per se.  This doesn’t make it fake, though.  It’s just mis-named.

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Is agate and jasper worth anything?

Seeing agates and jasper stones are so common, they aren’t considered all that rare.  However, it doesn’t mean they aren’t valuable.

What an agate or jasper is worth will depend on the size, look as well as the rarity.

For size, the larger pieces, as with all crystals, will always be worth more.  A smaller agate, for instance, may only cost a few dollars, whereas a piece weighing more than 10 pounds can be worth more than $100+.  Larger chunks are always worth more.

In terms of beauty, this would be the more important variable.  Colors, banding and clarity can all influence the price.  Mix this in with the size, and the price can greatly go up.  As beauty is in the eye of the beholder, it’s hard to say what defines beauty, but if it’s a rare piece color/banded wise, etc, you can expect more most of the time.

Lastly, some forms of chalcedony can be rarer than others.  As mentioned prior, these stones form during the crystallization process, which is when the stone is mixed with other minerals.  Rare mixed formations can generate a lot more value.

Summing it up

Agate and jasper are a chalcedony, which is based on two main things: the crystal size as well as the composition.  Chalcedony is a microcrystalline quartz.   Don’t confuse chalcedony with quartz, however, as there are differences.  The most important difference is simply by observing the luster of the conchoidal fracture surfaces.  Quartz will have a glass-like luster whereas chalcedony will be more of a dull luster.  If its translucent where only some light can pass through and no bands are seen, it’s a chalcedony.

To define an agate, it will be based upon three things:  the size, composition as well as if it’s translucent to semi-transparent.  If you can see through, it’s agate.

Jasper is based on three things, being crystal size, composition as well as opaqueness.  Remember, you can’t see through it because of the mineral material mixed in during the crystallization process.  Non-chalcedony material will interfere with the passage of light.

So, if you feel you have a piece of chalcedony, at a minimum, hold it up to the light to determine whether or not it’s a jasper or agate.  Can you see through it?  It’s an agate.  If not, it’s a jasper.  Yes, it’s that simple.

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About Me

Hi! I'm Lauren, and I run Moonlight Gems AZ. I'm an avid crystal collector and would love to share my expertise with you.