What type of rock is blue metal?

Blue Metal: What Is That Stuff, Anyway?

Ever heard someone mention “blue metal” on a construction site or at the garden supply store? It sounds kind of sci-fi, doesn’t it? But it’s not some exotic alloy. In reality, “blue metal” is just a common term, especially around Australia, for a type of crushed rock used in all sorts of projects i. Think of it more as a nickname than a precise geological term.

So, what is it, really? Well, most of the time, blue metal starts its life as either basalt or granite ii. These are tough, durable rocks, perfect for crushing into the angular bits we need for construction.

Basalt? That’s the dark, fine-grained stuff that comes from volcanoes iii. Imagine molten lava cooling quickly – that’s basalt. It gets its dark color from minerals like plagioclase feldspar and pyroxene iii. And sometimes, it has this cool bluish tint, hence the name “blue metal.”

Then there’s granite. Granite is the opposite of Basalt. It’s the coarse-grained rock that forms deep underground, cooling slowly over ages iv. It’s got that classic speckled look, thanks to minerals like quartz, feldspar, and mica iv. Depending on the mix of minerals, granite can also give you that bluish-grey color we’re after.

Why “blue metal,” though? Simple: it’s blue-ish, and it’s tough as metal i. Makes sense, right?

You see blue metal everywhere. Seriously, it’s the unsung hero of so many projects v.

• Concrete: It’s a key ingredient in concrete, adding strength and bulk v. I remember helping my uncle pour a concrete patio once, and the sheer amount of blue metal we mixed in was staggering. It really does make a difference.
• Roads: Blue metal forms the base layer of roads, driveways, and parking lots v. That angular shape helps it lock together tightly, creating a solid foundation.
• Drainage: Need to keep water from pooling up? Blue metal to the rescue v. It lets water flow freely, preventing all sorts of problems.
• Landscaping: It’s not just for construction, you know. Blue metal looks great in garden beds, pathways, and retaining walls v. A friend of mine used it to create a modern, minimalist garden, and it looks fantastic.
• Artificial Lawns: Blue metal dust can also be used under artificial lawns to stop weeds and plants from growing v.

Now, since basalt is a big source of blue metal, let’s talk types. You’ve got tholeiitic basalt, common in oceanic areas vi. Then there’s alkali basalt, often found near active volcanoes vi. And don’t forget mid-ocean ridge basalt (MORB) and ocean island basalt (OIB) vi. Each has its own unique story and composition.

So, how do they get this stuff out of the ground? It’s a pretty involved process. First, they clear away all the dirt and loose rock vii. Then comes the fun part: drilling and blasting vii. Boom! After that, they load up the broken rock and haul it off to be crushed and sorted into different sizes vii.

One thing to keep in mind: don’t confuse blue metal with bluestone viii. Bluestone is a broader term for various types of building stone. Blue metal is specifically crushed rock aggregate.

In a nutshell, blue metal is a versatile and essential material derived from crushed basalt or granite ii. Its strength, versatility, and distinctive color make it a go-to choice for builders and landscapers alike. So, next time you hear someone mention “blue metal,” you’ll know exactly what they’re talking about. It’s not magic, but it’s pretty darn useful.