Quartz vs Chalcedony: What’s the Difference?🤔

Added: 2026-05-12

[00:00:00]Today we are going to be addressing probably one of the more complicated subjects of mineralogy. It is the breakdown and explanation of silica or silicon dioxide, also known as SiO2. So, the first thing we want to understand is that silica, which actually you can find in those little silica packages, silica is quartz. Now, with silica, we're going to treat this like kind of the blood in our body. And this is always the way I try to explain it, especially when I'm talking to younger people or [music] teaching mineralogy. You know what I mean? I could get a blood transfusion from you. You could get blood from me if we have the same kind of blood type.

[00:00:38]When thinking of silica, we should think of an umbrella. First, we have your quartz, which is SiO2. But quartz is going to form as hexagonal crystals.

[00:00:47]Most of us know that these hexagonal crystals will have six sides that all come to a point. They [music] terminate.

[00:00:53]No, not the Terminator. But I do want to explain cuz some people go, "Well, not all quartz is six-sided." Because you could also have massive structures of quartz, [music] and that is also true.

[00:01:02]You can have massive crystals, most of which you might be familiar with as quartzite. [music] It looks like quartzite. Yeah. Which is basically metamorphic coming from sandstone. What that means is that typically [music] pure quartz sandstone becomes metamorphic, means it transformed sandstone into quartz crystals. Then we have something called chalcedony. Now, I know a lot of you are out there saying chalcedony and whatever else you're making up, but it's chalcedony. [music] Chalcedony is also quartz, SiO2, silicon dioxide. But it differs from standardized quartz because it is cryptocrystalline.

[00:01:38]Is that a form of currency in the crystal world? It means fibrous microscopic crystals. There's a lot of types of quartz out there, which are basically going to be made from impurities, [music] but they are still forming hexagonal.

[00:01:49]We're going to have amethyst, we're going to have smoky quartz. But with chalcedony, we have a completely different universe [music] of crystals.

[00:01:56]And let me break down some of them for you.

[00:01:59]Our first type of chalcedony that we want to talk about is agate. Agate is a type of quartz, which is a type of chalcedony, but it differs in the fact that it has concentric banding. And that's going to be [music] circular banding, okay? You see that there is a little geode hole right there, and then you see around the geode we're going to see concentric banding, meaning that it goes in a circular pattern. A lot of the times we can see agate having quartz around it. So, when we see amethyst geodes forming in the ground, most of the time we're going to see this banded agate growing around it.

[00:02:30]Next [music] is a very unique type of chalcedony, one I bet you didn't know was chalcedony. It's a green [music] type, green made green by nickel. And no, not nickel the type of money, nickel [music] as in the element, chrysoprase.

[00:02:46]Next type of chalcedony we want to talk about is onyx. [music] So, with onyx we're going to be seeing linear banding and not concentric banding. Now, some of you can tell the difference between an onyx and an agate. Now, most people are very familiar with black onyx, which is going to have the black and white lines.

[00:03:01]Unfortunately, for us we are completely sold out of that material at the moment, so I don't have it. But, this is a black agate or what people would call a black [music] phantom agate. And so, I just wanted to show this one in particular because it looks a lot like onyx.

[00:03:15]The next type of chalcedony that we want to talk about is carnelian, [music] which a lot of people also call an agate because sometimes it can have banding in it, but that's going to be more of a sard or what you'd call a sard onyx. So, [music] carnelian, what makes it unique and different from agate is that it doesn't have banding. And what's making carnelian red, which also makes sard or sardonyx red, is [music] iron oxide.

[00:03:37]Our last type of chalcedony that we're going to talk about today is jasper.

[00:03:42]It's what's called an aggregate, and an aggregate has microgranular quartz, kind of like little particles of sand that kind of all kind of bunch together and get [music] compressed into a mass, into a solid mass. So, this is essentially a solid mass of silica, of quartz. If you actually look at it on a different angle, [music] you can see the little crystals inside. Visually, there's a difference between jasper and carnelian because jasper is going to be opaque, where carnelian is going to be more transparent. [music] And typically with most jaspers, they're going to be solid in color, and they're going to range from so many different types, but we're going to see a lot of jaspers included in sedimentary stones, things like ocean jaspers, where there is a bunch of different things put together under one roof. And that's why you can also have several different types of chalcedony together in one stone. Now, let's summarize. Silicon dioxide, also known as silica or SiO2, is broken down into quartz and chalcedony. Quartz is going to be hexagonal [music] crystals.

[00:04:37]Chalcedony is going to be cryptocrystalline quartz. [music] First type is agate, which is going to have concentric banding. Onyx, which is going to have parallel bands, [music] mostly black and white. Chrysoprase, which is going to be colored green due to nickel.

[00:04:49]Carnelian, which is going to be red to orange via iron oxide. Jasper is an aggregate, it's a mass [music] of microgranular quartz. Now, that was a lot of information to digest, I'm sure some of you may know a lot of that stuff, some of you may not, but the point is is that it's time that we start really making these kinds of videos where we start really educating [music] and figuring these things out, as opposed to the whimsical things that are happening in our industry. Thank you everybody who watched up to this point, you made it through the whole video, I'm proud of you. Hope you learned something, and I'll see you next time.

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