You probably think… what kind of a question is this? ‘Do you know that agate can be crazy and on fire?’. Well, it is a funny question but it is true. I don’t know of another gemstone with so many varieties and therefore names, then the agate. What do you think about crazy lace agate, fire agate, Botswana agate, Condor agate, Brasil agate, flower agate, and so on?
You wonder are those varieties all agates? Why are there so many types? How can you recognize them all? What the h… is agate anyway?
Well, let’s start by giving you the answers. That’s what I am here for. And by the end of this blog post, you appreciate and love this beautiful gemstone even more than you do now.
What is the agate, besides a gemstone?
Agate is a rock formation, made of quartz, chalcedony, and silica. It occurs in many colors, but not so much in blue and green. And this beautiful gem is made in volcanic cavities. The agate minerals like to form an agate gemstone on another rock in those cavities.
When a volcano explodes gasses and fluids come out. The gasses make cavities when they are trapped in the fluid volcanic material. And the fluids, full of silica, fill up the cavities. Imagine you stand on the beach and the water comes in and flushes away again. Well, the silica-rich fluids come into the cavity and deposit their first layer. The second fluid wave comes in with a little different amount of silica and some other minerals. The result is that the second layer has a different color than the first one and the border between the two layers form a ‘band’.
Those layers consist of silica, quartz, and chalcedony. And sometimes there is not enough space in the cavity and in the layers of the gemstone the quartz is formed.
What about the different colors?
The different colors come from the different minerals that are present in the fluids that enter the cavity or vesicle.
The first layer is mostly green and when a fluid with iron oxide forms the second layer the color turns brownish or rusty. But also manganese, nickel, chromium, or even titanium cause of all kinds of different colors.
And sometimes when the agate is formed in the sedimentary rock you find little branches, leaves, or other organic material in the stone, giving it a different color, but also a different design.
The agate itself, like a rock, is not so special. The beautiful colors and designs come forward when the stones are cut and polished.
Where is the name coming from?
Although the agate stone is much older the first one to recognize the beauty of it is a Greek philosopher Theophrastus. He discovers the stone in the 3 or 4 centuries BC on the shores of the Achates River.
Since that time and since people know how to polish the stones, people use them for jewelry and as the bases of carved items (as decoration).
There is a story that a rich king in the Middle East uses agate to cover the floor of the meeting room of his palace. Workmen polish the stone until it looks like a mirror. And the king can look under the skirts of the female guests, just to make sure that they are female and no covered-up male spies.
Every color and every design form another variety.
There are so many different colors and designs that people give them a different name to distinguish them from other types of agate. Just to mention a few…
Crazy lace agate
has a very complex design and when you look at it closer you get ‘crazy’ of all the stripes and lines. You find it mostly in Mexico and the colors are red and white. Sometimes you see yellow and gray variations of the craze lace type.
There is also a blue lace variety, that is found in Africa. It’s very hard, mostly blueish, and also has a lot of ‘zigzags’ and ‘lines’.
is of course green and has a pattern that looks like moss. Although there is no moss inside or any other natural vegetation. The green color is ‘made’ by the minerals chalcedony and rusty iron hornblende.
is one of my favorites. You find them in all sorts of colors and you see an iridescent internal ‘fire’ in the stone. That fire is the combination of clear agate and hydrothermally deposited hematite.
are completely different since they are not formed by volcanic action. For example, Lake Michigan Cloud agate and the Lake Superior agate are formed in limestone and dolomite layers and have a marine origin. The colors are less specific and vivid and the bands are white and gray (Chalcedony).
is found only in Botswana and has typical bands and sometimes you find a ‘drusy’ of quartz in the vesicles of this agate type.
There are many more, but these ones are the most commonly used in pieces of jewelry.
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