Amphibole vs Pyroxene: A Tale of Two Rock-Forming Minerals  

Minerals are elemental compounds that form because of geological processes.

They’re necessary for virtually everything in life, even keeping humans healthy.

They’re also quite abundant in rocks. The specific composition, determines the rock type.

Amphibole and pyroxene are two common minerals often found in rocks.

Their similarities often make them indistinguishable to the untrained eye. But, there’s one very important way to tell them apart.

This guide delves deeper into both minerals to highlight their similarities and the qualities that set them apart.

Amphibole vs Pyroxene: Explained

What is Pyroxene?

Pyroxene is a mineral found in metamorphic and igneous rocks.

It refers to a class of vital silicate materials with the ability to form rocks.

They contain iron, magnesium, and calcium.

How Did Pyroxenes Get Their Names?

Pyroxene means fire stranger. In Greek, pyro means fire, and xenos means stranger.

It got its name because ancient Greeks found them in volcanic lava.

They stood out because of their crystalline appearance.

Still, some thought them impure.

This explains the stranger part of the term.

In reality, they are minerals that form when the volcanic process begins.

They crystalize when the lava erupts.

What Colors Are Pyroxenes?

Pyroxene mainly present as prismatic crystals.

Depending on the specific chemical process, they can range from dark green to black.

But, there are also some with colors like apple green, colorless, and lilac.

You can find pyroxene and a wide variety of metamorphic and igneous rocks.

Plus, its hardness on the Mohs hardness scale ranges between 5 and 7.

What is an Amphibole?

Amphiboles are a group of rock-forming inosilicate minerals.

Most comprise of minerals like iron ions, aluminum silicates, tetrahedral ions, and magnesium ions.

Depending on the chemical composition, amphiboles have a wide range of dark colors.

They include blue, black, green, and brown.

Why Are They So Easily Confused?

Nephrite and Jadeite are the only two minerals legally called Jade in the business world.

Jadeite is a pyroxene and nephrite is an amphibole.

Both minerals make pretty bangles, beads, and cabochons.

They also create small sculptures and a large variety of utility items.

The general characteristics and chemical composition of amphiboles and pyroxenes are alike.

But amphiboles are technically more complex than pyroxene.

They contain a hydroxyl group.

This makes them hydrous materials.

Pyroxenes, on the other hand, are anhydrous materials.

How To Tell Them Apart?

These two rock-forming minerals are so alike.

There’s really only one sure way to tell them apart. The secret to the identity of both is cleavage.

With amphiboles, the cleavage is parallel.

Plus, they’re less dense than similar pyroxenes.

How is an Amphibole Created?

These minerals form when convergent plates get exposed to heat and pressure.

This pressure builds up and causes regional metamorphism.

Amphiboles also form through the metamorphism of mafic igneous or clear sedimentary rocks.

What are Amphiboles Used For?

Amphiboles are a boon to the construction industry.

Their dark colors, attractive textures, hardness, ready availability, and polishability make them versatile.

For instance, contractors use amphiboles to build the interior and exterior of buildings.

They also use them for paving stones.

When crushed, they’re used for the usual applications.

These include railroad beds and road construction.

When builders use it like this, it’s used locally, near amphibious stores.

It’s not cost-effective to do it any other way.

Pyroxenes in the Lapidary Industry

Pyroxene usually happens in colorful gemstone-quality crystals.

Their mineral collectors love them.

When they’re cut into gems, they give their names to them based on their color.

For instance, triphane for yellow gems, hiddenite for green ones, and kunzite for pink ones.

The most essential gemstone in China is jadeite.

In Asia, high-quality jadeite can sell for prices of rival diamonds per carat.

Many present a bright green translucent gem.

It’s usually cut into beads, cabochons, and other lapidary uses.

Its green color is so bright they often use it as an imitation emerald.

But, there is a rarer type. It’s called star diopside and contains prismatic crystals of magnetite.

When polished and used with jeweler pieces like a cabochon, it looks like silver rays in a star pattern.

They use it in glassmaking and ceramics.

They also use it for biomaterials, fuel cell technology, and nuclear waste mobilization.

But, it’s not found in large enough quantities to make it economic mining and economic.

So there was synthetic diopside.

Pyroxenes in Ancient Times

These gems aren’t hard, but their tenacity is spectacular.

In this instance, it reveals jadeite is a durable material that’s resistant to breakage.

This made it useful for ancient people to make weapons and cutting tools.

Pyroxene in the Construction Industry

Pyroxene minerals are the primary and secondary components of a lot of rocks.

Specifically, the ones they use to make dimension, crushed, and architectural stones.

For instance, it’s the black granite that is popular for making decorative tiles.

Pyroxenes in Outer Space

Pyroxene minerals are abundant in meteorites.

We have also identified them in the rocks on Mars and the Moon.

Amphiboles and Asbestos

Amphibole minerals form circular and fibrous crystals.

They can produce tiny silicate fibers.

There is some evidence they linked the fibers to asbestosis.

It is a serious lung condition caused by asbestos exposure.

Asbestos is a material and commercial term for different minerals.

Its popularity was because of its electric and thermal insulators and qualities.

They also have fibers that make processing and extracting them easy.

But the tiny silicate fibers they produce wreaked havoc on the human immune system.

Overexposure for a long time creates serious inflammation of the lung.

This leads to respiratory failure, shortness of breath, and death.

They usually find this condition where people work in asbestos production plants.

These were the places where humans inhaled the toxic white dust.

The Bottom Line

Amphibole and pyroxene are essentially the building blocks of rocks.

Maybe even life. Like atoms and molecules, their existence is crucial to the planet’s existence.

Thus, it’s important we recognize amphiboles and pyroxenes for their similarities and differences.

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Amphibole vs Pyroxene