Agates are commonly found in the UK but are they crystals, minerals, or rocks? How do you tell if a rock is an agate? This article investigates how you can learn to identify agates
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Wondering if the crystal/rock/mineral you have found is an agate? Agates have accepted patterns but can be made up of multiple minerals – so it is easy to get confused. By learning accepted agate patterns, you can learn to easily assess whether or not you have an agate in the blink of an eye.
Let’s get to work!
What is an Agate?
Starting with the basics: what is an agate? These semi-precious stones are rocks made up of different colours of chalcedony, a silicate mineral. Chalcedony is a type of microcrystalline quartz. Some agates contain standard quartz. We call these quartz pockets.
Agates are special because each one is different. The chalcedony within them typically forms at different times, giving unique banded, fortified, and tubular patterns. Since chalcedony can be quite common, there are set patterns which are geologically recognised as agate patterns. We will examine each of these in greater detail below.
You can learn more about Scottish Agates in our previous blog, should you wish further reading.
Is Agate a Crystal, a Rock, or a Mineral?
Agates are classified as rocks because they are often made up of more than one mineral or crystal. However, they may also be made up of more than one microcrystalline type or colour of chalcedony. Technically, they are rocks which contain multiple minerals, though some of those minerals are the same type, if not the same colour.
Are Agates Worth Any Money?
Your agate may be worth money if it meets the accepted conditions for agates from that particular location. Much of the worth of an agate comes from where it is found. Other factors that may make your agate valuable include:
· What colours it has
· Which patterns are present
· How big it is
· How pretty it is
· If it is polished or faceted
If your agate has any structural damage which would prevent the cabbing, polishing, or shaping of the rock into jewellery, then it might not be worth as much as a good quality piece from the same location.
Polished agates of large size and good quality can fetch good money. Smaller agates with lesser patterns or colours are still worth something, it is finding a buyer without an established network which is the problem.
If your agate is Scottish we may wish to buy it from you. You can send us a message using the link on the side of the page, or through our email address at thestonecircleshop@gmail.com.
What Colour of Agate is Most Valuable?
This is a tricky question because it depends upon the area you found your agate in. If, for example, you found a green agate in Ayrshire, this would be remarkable and therefore worth more money. Ayrshire agates tend to be pink, grey, orange, and brown.
In general, green chalcedony/agate (chrysoprase) is valued. Purple chalcedony is also treasured. The least valuable colour of agate tends to be black and dark brown because these make it harder to see the patterns. Clear and white agates are similarly low value.
How to Tell The Difference Between Chalcedony and Agate?
A single, solid piece of chalcedony will be either the same colour throughout or will be a blend of colours, but none of which fall under the accepted list of agate patterns. If it is not a specific type of agate pattern, then your ‘agate’ might just be chalcedony. Don’t panic! Chalcedony is still beautiful!
How to Tell The Difference Between Quartz and Agate?
If you place white quartz and white chalcedony beside one another, you will notice that the chalcedony has a slightly off-white tinge, usually blue. Quartz pockets form inside agates all the time, so you should be able to spot quartz when it creates what we call a window into the rock.
Telling the difference between quartz and agate takes a while to master. However, keep comparing any white agates/chalcedony you find with the list of types of agate and you will work it out with persistence.
How to Tell if a Rock is an Agate?
Your rock may be an agate if it falls into the accepted list of agate types below. Other tips for spotting agates include holding the white chalcedony next to a piece of white quartz. You will notice it is more see through and has a cleavage like glass when broken apart. You will notice that the white of the chalcedony has an almost blue tinge by comparison to the quartz. Agates often have a dimpled looking skin which sets them apart from other rocks.
Tips for Spotting Scottish Agates
Tips for spotting Scottish agate include looking at the outer edge of the rock. Agates form in nodules in Scotland, usually with an inner pattern and an outer shell. The shell is usually a chalcedony skin. It will appear dimpled, as if rain has fallen on the rock and formed little pits. Not all agates follow this rule, but it is a good starting point.
Heads up about jasper and flint. Jasper can appear as the bright, glowing, orange carnelian. If it doesn’t have a glow and it isn’t semi transparent at least, then it is jasper and not a carnelian agate. If your rock is dark brown to grey and has a white/cream ‘skin’ on it, it could be a piece of flint/chert. These are a very similar material only really differentiated on a microscopic level – or by studying and learning the types of agate patterns listed below.
What is the Difference Between Agate and Common Opal?
Agate/chalcedony can also appear very similar to common opal. Although valuable opal is rare and you are unlikely to dig any up in the UK, common opal is…well…common. Telling the different is easy, fortunately, with a simple hardness test. Opal has a hardness of 5.5 and chalcedony has a hardness of 7. This means you can scratch opal with a steel knife, but not chalcedony.
Where to Find Agates?
Whether you are in Scotland or elsewhere, agates tend to form in old lava beds. These are only found in regions which are or were volcanic. Since the Ayrshire and central belt strip of Scotland is largely volcanic, you can find agates in the waterways on both the east and west coast, all the way up as far as Aberdeen.
Look for old volcano beds and then hunt for nodule shapes, you might get lucky and find a pretty agate!
What are the Different Types of Agates?
Wondering how to tell if a rock is an agate? The accepted agate patterns are listed below. You will find that some agates contain more than one of these features. You will also find that some pieces you thought were chalcedony, turn out to be agate once you have polished them. Don’t forget that you can pick up our PDF on hand polishing rocks or you can read more about where to get tumblers in the UK in our previous blog.
At the moment, we are using an Evans dual barrel tumbler running without the dual barrels, using a 3lb rubber barrel instead. The plastic barrels are noisier. We added a National Geographic rubber barrel and it works brilliantly. As quiet as we can get it. Anyway, back to the agates!
Banded or Fortified Agate
Banded agates, also known as fortified agates, are potentially the most prized. These have clear lines of different coloured chalcedony, usually running around the outside edges of the rock. The lines form ‘bands’ around the agate, although they may go in any and all directions. When these lines are straight, we refer to the agate as onyx. When the lines are parallel yet lead everywhere, they are banded or fortified agates.
Usually (in our experience) banding or fortification forms most often around quartz pockets. Quartz pockets resemble windows of white within your agate. Banded or fortified agates do not need to have a quartz pocket in the centre.
Lake Superior Agates and Botswana Agates are famous for their fortification. Coyamito agates, on the other hand, are famous for having banding around a central, glittering quartz pocket. When this cavity occurs we call them geodes.
Onyx Agates
An onyx agate is a banded or fortified agate where the lines on the face run parallel to one another. These are sometimes called water level marks or water lines. This creates an almost striped effect. Although onyx agate is typically dark in colour, it does come in multiple colours. For example, we recently found, polished, and sold, a pink onyx agate.
Watch out for the imitation material. Both green banded calcite and alabaster are used to mimic onyx agate. If you don’t know how to tell the difference, try to scratch your rock with a steel knife. A steel knife (hardness 5.5) is harder than alabaster (hardness 1-2) or calcite (hardness 3). If you can scratch your onyx then it isn’t onyx at all!
Dendritic/Plume Agates
Dendritic agates, sometimes called plume agates, have ‘plumes’ of inclusions within them. These look like tiny tree patterns (dendrites) or even feathers.
Sagenite Agates
Sagenite agates look like they have a spray of fine lines in them. These are often presented as a circular spray of fine needle-like inclusions which can be anywhere on the agate. These are usually secondary crystals which become embedded in the rock as it forms.
Grape Agate
Arguably one of the most beautiful types of agate out there, grape agate forms in botryoidal shapes, creating little bubbles of purple (rarely green) chalcedony. These resemble bunches of grapes, hence the title.
Tube Agate
Tubular agates have tubes running through them. The tubes don’t have to run all the way through. Many varieties of moss agate are actually tube agates in disguise.
Eye Agate
The eye agate has bullseye shaped patterns on it which resemble eyes. They have circles with concentric banding around them in multiple colours.
Brecciated Agate
Breccia is another way of describing when rocks are smushed together under intense pressure and heat. This forms a sort of broken-fault pattern in the agate.
Fire Agate
When botryoidal (bubbly) chalcedony meets the iridescence of iron oxides, you get fire agates. They look red or orange tinged with multiple colours throughout.
Sardonyx Agate
This type of agate has brown to reddish bands alternating with white and black. This type of agate is (in our collecting experience) the most similar to flint and chert. Sometimes you think you picked up chert but it sardonyx or onyx which is too hard to see. Sardonyx is onyx except with red or red brown bands.
Polyhedroid Agate
A Polyhedroid Agate has a flat sided shape and contains polyhedrons stacked together on the inside. It is suggested on Geology that this agate only comes from Paraiba State in Brazil.
Types of Agates – Commercial Names
Although the agates above are the technical names, crystal sellers often give agates commercial names which make them more appealing or which refer to their location. For example, Lake Superior Agates are known for their fine banding.
Here are some other commercial names for agate which you might encounter. These lists are by no means exhaustive. If you want a really exhaustive one, check this article on Minerals.net.
Iris Agate
These are fortified agates which have been sliced very thinly. Again, this is another commercial name. Iris agates are beautiful when held up to the light, often displaying iridescence. Iris agates are sometimes called rainbow agates.
Crazy Lace Agates
Crazy Lace Agate is a commercial name for a fortified/banded agate that has multiple parallel lines all facing different directions. Lace agates are fortified agates which are usually blue and have the effect of lace. Crazy lace is when that lace gets cray-cray.
Blue Lace Agate
Similar to crazy lace agate, blue lace agate is a soft, fortified, blue tinged agate. This commercially named stone typically comes from Africa and the fortification lines are fuzzy, as they might be if they were made from lace.
Enhydro Agate
Enhydro crystals, rocks, or minerals, are those which have water trapped inside them. It may just be a single drop. These have recently become very popular – but we warn you, there are dozens of fakes for every real one. Agates are probably one of the more likely rocks to contain water since they have a propensity towards geode formations, which leave that central hole. However, when you see enhydro quartz, enhydro amethyst, enhydro any other straight form of mineral, then you should be at least a little suspicious.
Picture Agates
Picture agates are named because they resemble paintings. They could contain waterlines, dendrites, or any combination of patterns, but always look pretty as a picture. Picture agates might also be known as Landscape Agates and scenic agates.
Agates Named for Location
There are several agates named after the location they come from. These include Laguna agates (from Ojo Laguna, Mexico), Botswana agates, Lake Superior agates, Coyamito agates, Moctezuma agate, Oregon Snakeskin agate, Condor agate, and Fairburn agate. There are others and this list is not extensive.
What are Thunder Eggs?
Although our source says that these mostly come from Oregon, we have seen more thunder eggs from Australia. This might be a colloquial term. A thunder egg is similar to a geode but usually consists of rhyolite as opposed to chalcedony. They can contain opal. These are both volcanic nodules.
A Special Mention for Moss Agate
Moss agate is not technically agate because the mossy pattern is not recognised as one of the traditional agate patterns. Nonetheless, we call it moss agate because it contains different colours and textures of chalcedony, sometimes with inclusions, which meet the other criteria for winning the agate title. As such, the industry commonly refers to this type of chalcedony as moss agate.
How to Identify Agates: Real vs Fake?
If your agate is a brilliantly bright blue, pink, green, yellow, orange – or any other bright colour, put it in salt water for a few days. The dye will leak out into the water. Dyed real agate is far more common than the fake glass agates usually made in China. The horrible thing about dyed agate is that the crystal probably started off as something really beautiful, but someone thought it could be even better if they added dye. Yuck.
Unfortunately we can’t give you an example because we don’t sell it. However, if you look on this page of Amazon you will see enough dyed agate to fill a whole rainbow. Note that we are deliberately pointing no elbows…
Glass agates are becoming more common. These appear to have whorls and swirls of banding through the stone. They can be very convincing. Here is how to tell if your agate is real or fake though: scratch it with an ordinary steel nail. A steel nail has a hardness of 6.5 while a real agate has a hardness of 7. If the knife scratches the agate, then it is glass, which has a hardness of 6.5 on the Mohs hardness scale.
Are Agates a Healing Crystal?
Although we are mainly focused on the properties of agates which you can see, there are those who use agates as healing crystals. They are used for uncovering hidden layers of yourself. Excellent for doing shadow work and for a stone which can hit more than one chakra point at once.
Each agate is completely individual and has a unique energy to it. You may well be attracted to one stone and never look at others. In terms of crystal healing, the agate is one of the most diverse stones you can buy.
You can study up on healing crystals then check out Crystals for Beginners on Amazon. Katriona is currently reading Focus on Crystals, by Edmund Harold, if you would like to progress from beginner level.
Where to Buy Agate Online?
You can buy Scottish agates through the Stone Circle website. Browse our agate section or visit our Etsy page for more. We only sell genuine, non-dyed, self-collected, sometimes even hand polished or tumbled Scottish agates. We either find them ourselves or buy them from other Scottish Rockhounds.
Shopping for agate? Expanding your collection of crystals, rocks, minerals, or looking for healing crystals for sale? The Stone Circle provides ethically sourced crystals, minerals, rocks, and agates, from all over Scotland. Shop now and find your favourite natural stone.
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