Jasper vs Chert – The Similarities and Differences (With Photos)

By Keith Jackson - Geologist

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Jasper vs Chert – The Similarities and Differences (With Photos)

By Keith Jackson - Geologist


Chert and jasper are both rocks that look pretty similar, but there are ways to tell them apart. To differentiate chert vs jasper, you need to know what makes each one unique.

Chert is usually found in colors like white, gray, or brown and has a more uniform look. Jasper, on the other hand, is often more colorful and has a lot of patterns.

Both of these stones are used for making tools and jewelry because they’re hard and can be shaped into beautiful items. They share some characteristics, but they also have differences that can help you tell which is which.

Chert vs Jasper – The Major Differences

Exploring how chert and jasper differ can be pretty interesting. We’re going to dive into what sets these two rocks apart.

Appearance – Jasper displays a variety of patterns.

orange, white, and black jasper sphere
Jasper provided by TerraDawnMinerals

Chert has a look that’s pretty smooth and consistent, almost like looking at a solid piece of rock without much going on. Sometimes, you might see some bands or layers, but that’s as fancy as it gets.

Jasper is more like the life of the party, showing off with all kinds of marks, lines, and dots. It’s like each piece has its own unique story or design, making it stand out.

While chert keeps it simple and straightforward, jasper brings variety and excitement with its array of designs. It’s the difference between a plain notebook and one covered in doodles and drawings.

Colors – Chert comes in more subdued and earthy colors.

egg-shaped chert cabochon with brown bands
Chert provided by gemstonesworld

Chert usually sticks to a simple color palette, mostly hanging around the white, gray, brown, or black shades. Sometimes, it’ll surprise you with a bit of color, but that’s not too common.

To tell chert vs jasper apart, just look at the colors. Jasper loves to show off in reds, yellows, greens, and even blues, thanks to all the different minerals mixed in with it.

While chert keeps things pretty basic with its colors, jasper brings a whole rainbow to the table. It’s like comparing a classic gray sweater to a bright, patterned one.

Luster – Jasper doesn’t shine as much.

red and green polished jasper flame
Jasper provided by steingo

Luster is how a rock shines or reflects light, kind of like how some surfaces are shiny and others are not. Chert has a waxy shine, making it seem like it’s lightly coated in candle wax when you see it shine.

Jasper’s shine is a bit different; it can range from being kind of dull to having that same waxy glow. This means sometimes jasper doesn’t catch the light as much, but when it does, it has a soft shine.

Formation – Chert is formed from the remains of marine plankton.

reddish brown rough chert
Chert provided by RockPaperAndSisters

Chert is made in a pretty cool way. It comes from tiny bits of silica that come from the remains of microscopic creatures, all gathering together in places like lakes and oceans.

Jasper, on the other hand, forms because of volcanoes. When a volcano erupts, it sends out ash and other stuff that’s rich in silica, and over time, this stuff turns solid and becomes jasper.

So, if you’re into looking for these rocks, knowing where they come from helps. If you’re wondering where to go rockhounding for these rocks, think about these terrains to find the best spots near you.

Fluorescence – Some types of jasper can glow under ultraviolet light.

blue, red, and white jasper sphere
Jasper provided by NaturalArtMinerals

Fluorescence is when a rock glows under a special kind of light called UV light, which is not something every rock can do. Chert is one of those rocks that doesn’t really glow, no matter what kind of UV light you shine on it.

On the other side, jasper can be a bit of a show-off with this cool glow-in-the-dark trick. Some types of jasper can light up in different colors because of the special stuff mixed inside them.

Price – Chert is relatively inexpensive.

two banded chert cabochons
Chert provided by EmsgemstonesOR

Chert is pretty affordable because it’s found in a lot of places and isn’t too rare. This means you can pick up chert without spending much money, making it a good choice if you’re just starting to collect rocks.

Jasper, though, can get a bit pricier. The colors and patterns it has, plus where it comes from, can make some jasper pieces more special and sought after, raising their price.

Our guide to what jasper is worth can help you figure out what you can expect to spend.

Location – Jasper can be found in volcanic areas.

rough red jasper
Jasper provided by NecklacesCreative

You can find chert in lots of places all over the world, mixed in with sedimentary rocks or as cool nodules in limestone.

Jasper, on the other hand, hangs out where volcanoes are or were active. It’s part of the volcanic rock family, which means it’s often found in places that have seen some fiery action.

If you’re on the hunt for chert and jasper, we have a guide that can help you find crystals near you,

Jasper vs Chert – The Similarities

Even though chert and jasper seem different, they actually share a lot in common. Here’s what makes these two rocks more alike than you might think.

Streak – Both rocks leave a white streak.

rough gray and white chert
Chert provided by MyLostGems

Streak is what you see when you rub a rock on a piece of unglazed ceramic tile. It shows the true color of the rock’s powder, which can be really different from the rock’s surface color.

Even though chert can be pretty plain looking or jasper can have all sorts of colors, they both leave a white streak when tested. This white streak means their powder form looks the same, no matter what color they are on the outside.

Clarity – Jasper is typically opaque, and so is chert.

teardrop shaped jasper with red and yellow streaks
Jasper provided by Fossilera

Clarity describes whether you can see through a rock or not. If a rock is clear, you can see through it, but if it’s opaque, you can’t see through it at all.

Chert doesn’t let any light through, so you can’t see through it just like you can’t see through a brick wall. It’s totally opaque because of how tightly all its tiny pieces are packed together.

Jasper is the same way; it’s also opaque, meaning no light passes through.

Hardness – The two rocks have a hardness of 7.

rough brown chert
Chert provided by AlbionFireAndIce

The Mohs hardness scale is a way to tell how hard different minerals are, with scores that go from 1 to 10. On this scale, 1 is super soft and 10 is super hard.

Chert and jasper both score about a 7 on this scale, which means they’re pretty tough. They’re hard enough to scratch softer minerals and resist scratches from things lower than them on the scale.

So, if you have a piece of chert or jasper, you can bet it’s not going to get scratched up easily. This makes both of them great for things like jewelry or tools because they last a long time without showing wear.

Crystal Structure – Chert and jasper are types of microcrystalline quartz.

brown and gray rough jasper
Jasper provided by RelicGemstones

Crystal structure is the way the tiny bits that make up a rock are arranged. Imagine it like how bricks are put together to build a house. For rocks, it’s the way their molecules fit together.

Chert has a special setup called microcrystalline, which means its crystals are super tiny, way too small to see without special tools. It’s like they’re made of microscopic building blocks.

Jasper has this same kind of structure. Even though jasper can look really different from chert because of its colors, inside, it’s built pretty much the same way.

Cleavage – Each rock has a conchoidal fracture.

gray chert shard
Chert provided by ShivaranCrystals

Cleavage refers to the natural breaking point where rocks split easily along certain lines, kind of like how wood splits best along the grain. But chert and jasper don’t really have these natural splitting points.

Instead of splitting neatly, both chert and jasper break in what’s called a conchoidal fracture. This means they break off in curved surfaces that can be really sharp, which is why they were perfect for making tools in the old days.

Chemical Composition – Both chert and jasper are made of silicon and oxygen.

green and peach patterned jasper slab
Jasper provided by AbstractRockShop

Chemical composition is like a recipe that tells you what a rock is made of. Both chert and jasper are mostly made of something called silicon dioxide, which is what quartz is made of.

Despite the difference between chert and jasper, at their core, they’re made of the same stuff. Chert is pretty straightforward with its makeup, while jasper gets its variety of colors from extra bits and pieces mixed in.

Density – The two minerals feel about the same when weighed.

brown and tan banded chert
Chert provided by LittleLemuria

Density is basically how much stuff is packed into a certain amount of space in a rock. Think of it like comparing a backpack full of books to one that’s just holding a few; the one with more books is denser.

Chert and jasper are both pretty packed with stuff, mainly because they’re made of the same thing: silica. That’s why they feel pretty solid and heavy for their size.

Even though jasper might be a tiny bit heavier because it has extra minerals mixed in, the difference is very small. So, if you were to hold a piece of chert in one hand and a piece of jasper in the other, they’d feel almost the same in weight.

Magnetism – Neither rock is magnetic.

green patterned jasper sphere
Jasper provided by Fossilera

Magnetism is when a rock or anything else can pull on metal objects, kind of like how magnets stick to your fridge. But when it comes to chert and jasper, they don’t have this pull; they’re not magnetic.

Both of these rocks just sit there and won’t grab onto a magnet if you hold one near them. This means you can’t use a magnet to pick them up or make them move.

So, if you’re playing around with a magnet and wondering if it’ll work on chert or jasper, the answer is no. Neither of these rocks will react, making them pretty similar in this way.

Conductivity – Both rocks are poor conductors.

rough black chert
Chert provided by DyttleDru

Conductivity is about how well something can pass electricity through it. Imagine trying to send a secret message through a string tied between two cans; if the string is good, the message goes through easily.

Chert and jasper are like strings that aren’t very good at carrying messages. They don’t let electricity travel through them well, making them poor conductors.

The Easiest Ways to Tell Chert and Jasper Apart

Finding out the differences between chert and jasper can be pretty interesting. We’re going to explore how you can tell these two rocks apart.

Color Inspection

green, white, and red polished orbicular jasper
Jasper provided by DesertRoseCrystals7

If you’re trying to figure out if a rock is chert or jasper, the first thing to do is check its color. Chert is often found in simple, earthy tones like white, gray, brown, or black, making it pretty plain.

Jasper stands out more because it comes in brighter colors like red, yellow, green, and sometimes even blue. These colors are much more eye-catching compared to the more subdued shades of chert.

So, if you have a rock and you’re not sure what it is, look at how colorful it is. If it’s got bold and bright colors, it’s probably jasper; if it’s more on the muted side, then you’re likely holding a piece of chert.

Examine for Patterns

round gray and tan banded chert cabochon

To figure out if you have chert or jasper, take a close look at the stone’s surface. If you see lots of lines, spots, or bands, you’re probably looking at jasper because it’s known for having these kinds of patterns.

Chert, on the other hand, doesn’t really show off like that. It has a more consistent look, though some pieces can have banded patterns.

Test for Fluorescence

peach and white jasper cabochon
Jasper provided by ZenergyJewelry

You can use UV light to check your rock for fluorescence. Chert usually doesn’t light up under UV light, so if your rock doesn’t glow, it might be chert.

Jasper, meanwhile, can glow in different colors. This glow comes from certain things mixed in the jasper that react to the UV light.

About Keith Jackson - Geologist

Keith Jackson is an avid rockhound who is constantly exploring new sites to expand his collection. He is an active Geologist with a wealth of experience and information from across the country that he loves to share with the Rock Chasing crew.

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