Augite
Calcium Sodium Iron Magnesium Aluminium Inosilicate
Chemical Formula: (Ca,Na)(Mg,Fe)(Si,Al)2O6
Crystal System: Monoclinic
Crystal Habit: Commonly as stubby prismatic crystals, also acicular, skeletal, dendritic (= branched)
Mohs Scale: 5,5-6
Tenacity: Brittle
Fracture: Conchoidal
Color: Black, brown, greenish
Streak: Greenish-white
Luster: Vitreous
Diaphaneity: Opaque to translucent
Augite: A Common but Complex Mineral
Have you ever picked up a dark, shiny rock and wondered what it was? There's a good chance that if it was heavy, with a slightly greenish tint, it could have been a piece of augite. Augite is a super common mineral found all over the world and is an essential part of many different types of rocks. In this article, we're going to dive into this fascinating mineral, exploring its definition, origins, properties, and historical significance.
Why is Augite Important?
Augite might look like just another dark, shiny rock, but it tells a rocking story! Here's why geologists care about it:
Earth Detective Work: Augite is formed deep inside the Earth under intense heat and pressure. When volcanoes erupt, they carry augite from the depths to the surface. So, finding augite in volcanic rocks gives us clues about what's happening way down below where we can't actually go.
Recipe for Rocks: Different types of rocks have different 'recipes'. Augite is a main ingredient in rocks like basalt (the stuff that makes up Hawaii's black beaches) and gabbro (a rock found deep in the Earth's crust). Understanding where augite is found helps geologists figure out the different types of rocks that make up our planet.
A Time Traveler's Tale: The special mix of elements inside augite can change depending on the conditions where it formed. By studying it, geologists can guess things like the temperature and pressure under which that rock was 'baked'. It's like looking back in time!
Word Origins: A Little Bit of Greek
The word "augite" comes from the Greek word "augites," which means "brightness" or "luster." This name comes from how augite crystals can catch the light and look shiny.
The Look of Augite
Here's how you would spot augite in the wild:
Color: Usually dark green, brown, or black. Sometimes it can even have a hint of purple!
Shape: Augite forms short, chunky crystals. Picture a little rectangular block, kind of boxy in its shape.
Shine: It has a glassy shine, although sometimes it can look a little duller.
Breaking Apart: Augite has something called cleavage. That means if you hit it just right, it breaks cleanly along flat surfaces, almost like it wants to break into slices.
A Bit of History
Augite was first formally described as a mineral way back in 1792 by a German scientist named Abraham Gottlob Werner.
Today (2023), augite isn't used for fancy jewelry or anything like that. Its real value is in what it teaches scientists about our planet's fiery past.
Fun Facts
Sometimes augite gets mistaken for a totally different mineral called hornblende. They are both dark in color, but a geologist would know the difference by their shape and how they break apart.
Augite can be found on other planets too! It has been identified in some meteorites from Mars, giving us clues about the Red Planet's inner workings as well.
Think of it this way: Augite is like a tiny history book buried in rocks. By understanding this common mineral, scientists unlock the secrets of volcanoes, the recipe of our Earth, and even what conditions might have been like on other planets. It may not be as flashy as gold, but it's pure scientific treasure!