Chalcedony vs Quartz: What Are They, And What's The Difference?

Chalcedony and quartz are two crystals that are commonly confused.

They can have some similar traits that can make it difficult to tell the two stones apart.

But, there are some major differences that create a clear distinction.

Chalcedony vs Quartz (Explained)

What is Quartz?

To be able to tell the two stones apart, it is important to understand what makes them unique.

Quartz has a chemical composition of mainly silica.

Many different gemstones are types of quartz, including citrine, amethyst, rose quartz, and smoky quartz.

It is both the most common crystal and the most common mineral on Earth, found in abundance all over the world.

It comes in colors across the entire rainbow spectrum.

Aside from being a pretty crystal to use in jewelry and decorations, it is an incredibly durable stone that is also heat resistant, making it very useful in all types of household items.

A common use for it is in kitchen countertops due to its staying power.

What is Chalcedony?

Chalcedony is actually a combination of quartz and a stone called moganite.

So, the only real chemical difference is that chalcedony has additional stone fibers.

It comes in blue and white colors and is found all over the world.

A popular stone for jewelry, it can also be seen in decorative purposes.

Some use it in spiritual practices, as it is thought of as a very spiritually powerful stone for dissolving negative energy.

Common identification methods

Although the two stones can often look similar, there are some pretty simple ways to tell the two apart.

Here are some differences that can help you discern the type of stone that you have.

What is its formation?

If it comes in the classic crystal cluster, that’s a sure-fire way to help you identify quartz.

When you think of a crystal and see the different sparkly spears sticking up, then that is how quartz most commonly presents itself.

However, quartz can also be found within geodes (a plain looking stone when, cracked open, reveals crystals on the inside), as clear stones on the ground, or even as small grains.

Although chalcedony is composed of microscopic crystalline structures, it is usually found as a single glassy stone instead of in crystal clusters.

It is also found inside geodes, but instead of the pointy crystalline structure we find with quartz, it can have small round crystal clusters or a flat surface, similar to agate.

What is the color?

Quartz comes in a wide variety of colors, so you can’t tell a quartz crystal purely from the color.

Chalcedony, on the other hand, is either white or blue; if it is a different color, it is not called chalcedony, even if it has a similar chemical structure.

So, if you find a sparkly crystal of yellow or purple, you can be absolutely sure that it is not chalcedony.

What is the transparency?

Quartz is a very transparent stone, no matter the color.

Light should be able to be shone straight through, and some very clear pieces of quartz will even allow you to see through to the other side.

Sometimes it has a milky or frosted appearance, but the transparency will still be high.

If it is found within another rock, it will appear darker and less translucent, but, if broken out of the rock, will reveal its transparent nature.

Chalcedony is generally a semi-transparent stone.

It is not completely opaque, but also is not super transparent.

You could illuminate it with a light, but the light wouldn’t shine through very well.

This is a great way to tell the difference between the two stones.

What is the luster?

Luster refers to the light that crystals reflect.

Quartz should have a luster similar to glass.

It is a very sparkly stone and is able to reflect light easily, which is one of the things that makes it a highly desirable crystal, and easy to spot when hunting for crystals.

Chalcedony, however, has a rather waxy luster, again, similar to agate.

It does not reflect light very well, but can be softly illuminated.

Similarities

Although the two stones differ in many ways, they also have several qualities similar to each other.

Here are some ways in which the two stones are related.

Where they are found

Both quartz and chalcedony are found all over the world.

Quartz is much more abundant than chalcedony, but they both have wide geographic reach.

Their number on the MOHS hardness scale

Quartz is a 7 on the MOHS hardness scale, making it a very hard and durable rock.

To check for the hardness, find a common household item that’s slightly lower on the MOHS scale, such as glass.

If the crystal is able to scratch the glass, then it means it’s higher up on the scale, indicating that it is most likely quartz.

Chalcedony has a similar hardness of 6.5-7.

You can perform the same hardness test on chalcedony that you can perform with quartz.

Try scratching a piece of glass with your piece of chalcedony and, if it is able to produce a scratch, it means that it is most likely of the correct hardness.

Chemical structure

Although their structure is different on the outside, they have a similar chemical structure.

Both stones are mainly composed of silica materials and they both have inner crystalline structures.

The reason why they look different on the outside is that quartz has a trigonal crystal structure, while chalcedony contains both quartz and moganite, another silica material.

This microscopic distinction makes a huge difference to the naked eye.

Why they are so often confused

Chalcedony and quartz have a history of being mistaken for each other.

Although they are two distinct stones, it is easy to see why.

They can have similar colors, both are very commonly found all over the world, and they have comparable hardness; chalcedony and quartz even have related chemical compositions.

They are both found in geodes and chalcedony’s limited transparency can be mistaken for a milkier quartz crystal.

But their similarities are limited, and some geologists even consider chalcedony to be its own mineral species.

Both chalcedony and quartz are beautiful stones.

This can help make it challenging to tell them apart.

But, it is useful to gain the skills in differentiating the two so that you can use each of them to their fullest potential.