How Hard is Andesite? Exploring Its Mohs Scale Hardness and Mineral Composition

Well now, let me tell ya, when it comes to rocks, this here andesite is a tough one. You see, it’s one of them rocks you’ll find when a volcano decides to spit out some hot lava and it cools down quick-like outside. They call it an “extrusive igneous rock,” fancy words for it coolin’ fast on the surface of the earth after a big ol’ eruption. So, this andesite ain’t like your regular stone you might find in your garden, no ma’am. It’s tougher, harder, and a lot more complicated in its makeup.

Now, if ya take a look at the hardness of andesite, it sits pretty at around 6 to 7 on the Mohs scale. That means it’s tougher than a lotta rocks you see on the ground, but not as tough as somethin’ like quartz, which is about a 7 or 8. So, it can take a little wear and tear, but don’t go hittin’ it with a hammer too hard, or it might crack on ya.

Andesite’s got a funny look to it, too. It can either be real fine-grained, like tiny bits you can’t hardly see, or sometimes it looks a bit chunkier with bigger bits of minerals in it. That’s what they call porphyritic, which just means it’s got both small and large grains inside. The rock’s made up of a mix of minerals, with the main one bein’ feldspar. Now, feldspar, that’s a mineral you’ll find a lot in these types of rocks. They say at least 65% of the feldspar in andesite is plagioclase, which is just a fancy way of sayin’ it’s a type of feldspar.

What’s real interestin’ is that andesite don’t have much quartz in it, less than 20%, so it’s not as shiny as some other rocks that have more quartz. And it’s low in alkali metals too, so it’s not like one of them rocks you might find in your salt shaker. But don’t let that fool ya, it’s still a strong rock.

Now, I’ve heard folks talk about how the density of andesite can change depending on how much space there is between the minerals in it, but most of the time, it’ll be around 2.8 to 3.0 grams per cubic centimeter. So, it’s a pretty heavy rock, especially if you were to pick up a chunk of it.

Andesite’s got a good bit of strength in it, too. The strength can range anywhere from 86 to 203 MPa, depending on what part of the rock it is and how much pressure it’s been under. But let me tell ya, it’s strong enough to hold up in all kinds of conditions, even when you stack it up in buildings or use it to make roads and such.

In them fancy charts they use to tell the type of rock, andesite ends up in the basalt field, which is another type of volcanic rock. So, if you see a rock that looks like andesite but feels a little different, it could be a type of basalt. They’re close cousins, I reckon, both born out of volcanoes.

So, when you’re out walkin’ and you see some of that greyish rock, it might just be andesite. It’s one tough rock that’s been around for a long time, thanks to them fiery volcanoes spittin’ it out for us to admire and use. But just remember, it ain’t as soft as you might think. It’s got some bite to it, just like a good ol’ piece of stone should!

Tags：[andesite, hardness of andesite, volcanic rock, Mohs scale, feldspar, igneous rock, basaltic andesite, rock strength]