Geology is just one of the many scientific disciplines that have fascinated me over the years. As a teenager, I became fanatical about collecting rocks, rock minerals, crystals and fossils, every specimen of which I arranged fastidiously along the wall shelf that overlooked my desk (see photo below). I am proud to say that this extensive collection has been lovingly preserved in its original arrangement by my mother, starting with translucent colourless quartzite crystals, ranging right through the colours of the rainbow and ending with opaque, jet black fragments of obsidian. Dust and the occasional long-dead beetle aside, not a single rock has been discarded. They’re all there and they’re all special. I would like to extend a thank you to my mom for preserving my collection, although it wouldn’t hurt you to dust once in a while…
Collecting Rocks is Not Just for Boring People
Why on Earth would anyone collect rocks? Well, rocks tell us about the history of the ground underneath our feet and you don’t need to be terribly nerdy to appreciate that! Unfortunately, too large a percentage of that ground has been covered in concrete, ceramic tile, plush carpets, hardwood or laminate (if you’re a cheapskate.) But beneath the man-made veneer of our planet lies a fabulous variety of rock types, minerals and crystals, each with a history, each with a unique set of properties, each comprising a piece of the puzzle that, once put together, tells the story of the formation of the Earth and how the land came to be shaped the way it is.
My deep interest in mineralogy and geology was and is about more than just the pretty appearance of certain rock minerals and crystals. It’s about their unique properties, characteristics and traits, a handful of which you will come to learn about in this two-part blog. Of the many rock minerals I have collected over the years and encountered during my University geology classes, there are some that have remained firmly lodged in my memory, just like pyroclasts in a volcanic breccia. These are the rock minerals that, in my mind, are true testaments to the sheer awesomeness of the natural world.
And the Nominees Are…
Firstly, in the interests of scientific rigor, let me stipulate the following: this list is totally subjective, so forget the part about “scientific rigor.” The facts I present, however, are true! Secondly, my choice is restricted to rock minerals or gemstones. Not rock types, such as marble, granite and shale. Minerals are the building blocks of rocks, just like desperate and marginally talented 20-something year old girls are the building blocks of girl groups.
Granite, for example, generally consists of three different rock minerals: Scary Spice, Baby Spice, Fanta Pants and one that looks like a lesbian. Hold on… I’m getting confused. That’s four spices.
Anyway, you get the point, so now that you know what a rock mineral is, let’s get to it! Get your De Beers on ‘cos we’re going digging!
Awesome Rock Mineral # 1: Iron Pyrite
AKA: Fool’s Gold
Chemical Composition: Iron and sulphur
Why it makes this list: Iron pyrite crystals are one of the most incredible demonstrations of symmetry in nature.
Name Origin: Pyrite originates from the Greek word for “fire”
We tend to think of nature as being random and chaotic, but rock crystals are a beautiful example of how there is more flawless pattern and symmetry in nature than there is entropy and disorder. Iron pyrite is one of my favourite examples, with its brassy yellow crystals that are seemingly impossibly square in shape. Pyrite frequently grows in great tangles of inter-grown geometric shapes, most commonly cubic and octahedral. The result is both incredibly beautiful and intriguing: something that could pass as the work of an abstract artist on acid.
Iron pyrite has been dubbed “fool’s gold” owing to its glistening metallic yellow colour, which makes it look quite similar to gold; one of the most coveted elements on Earth. There are many differences between pyrite and gold, of course, but the most important to mankind is that iron pyrite is appallingly common and is likely to get an icy reception from your wife or girlfriend if given as a gift.
Then again, Jessica Simpson is living proof that you can be appallingly common AND rich at the same time.
Awesome Rock Mineral # 2: Diamond
AKA: A girl’s best friend.
Chemical Composition: Carbon and sometimes trace elements
Why it makes this list: Diamond doesn’t need an excuse to make this list.
Name Origin: Diamond comes from the Greek word adamas meaning “unconquerable” or “invincible.”
Diamond is the Chuck Norris of gemstones. It’s hard, it’s tough and it’ll charm the pants off any lady. Formed deep in the Earth’s crust under conditions of bone-pulverizing pressure and temperature, diamond is the hardest known substance in existence and it wins this title by a very, very, very large margin.
When cut correctly, diamond’s reflective and refractive properties emit a kaleidoscopic disco of light, coruscating with every colour of the rainbow. Uncut, diamonds are translucent and have an almost greasy or soapy lustre; certainly not something one might describe as breathtakingly beautiful. Most ladies prefer it cut. Their diamonds too.
An uncut diamond, which just goes to show how important cut is to the aesthetic appeal of this gemstone.
In addition to their aesthetic appeal, which has been adored and worshipped by cultures and civilizations across the world for centuries, diamonds also have rather useful modern applications. Actually, 80% of all the diamonds unearthed are exploited for their incredible strength as blades, grinders, bearings and drill bits. The other 20% are considered too pretty to be used for drilling open rotten teeth and so they are square-cut and pear-shaped, these rocks don’t lose their shape DIAAAAMOOOOOONDS…
There are many things that make diamonds exceptionally awesome: they’re the only gemstone composed of a single element (carbon), they’re the hardest substance known to humankind, they’re incredibly beautiful and they’re incredibly expensive. But the bottom line really is that diamond’s awesomeness transcends time, culture, civilization and class. Diamond is king (and a giiiiiiiiiiiiirl’s beeeeeeeeest frieeeeeeeeeeend!)
Awesome Rock Mineral # 3: Fluorspar
Chemical Composition: Calcium and Fluorine
Why it makes this list: For its, like, totally insane property known as thermoluminescence.
Name Origin: “Fluo” is the Latin word for “to flow.”
I first came across Fluorspar on a seven-day canoe trip down the Orange River, which is the natural border between South Africa and Namibia. On our fourth or fifth day, the guides pulled the canoes off the river onto Namibian shores and took the younger whipper-snappier of us on a gruelling 45-minute hike up the steep, boulder-strewn slopes. At the summit, we found an old abandoned fluorspar mine. There were just piles of this translucent green and purple mineral lying everywhere. So, we all filled our pockets and headed back down towards the camp.
That night, our chief guide showed us just why fluorspar was so damn cool. Onto the searing-hot coals that were the remainder of our nightly camp fire, he cast a handful of broken fluorspar shards and dust. After a few seconds, these rocks started to glow bright electric blue and green before shattering like popcorn into smaller fragments. In spite of the burning-hot bits of shrapnel that were sent whistling past our heads, we were enraptured by the performance and I have used fluorspar to impress girls ever since.
Unfortunately, I have run out of fluorspar.
Fortunately, I have my personality to fall back on.
Fluorite is the trance party-goer of the mineral world
Fluorspar or fluorite most commonly comes in cubic crystals, although the one’s we found on the Orange River had all been shattered or broken at some stage and so ranged in amorphous size. “Fluo” is the Latin word for “to flow” and this name was given to this rock mineral for its applications in iron smelting. In a peanut shell, fluorite decreases the viscosity of molten iron, helping it to flow better.
It was only after the discovery and naming of fluorite that its awesome physical properties of fluorescence and thermoluminescence were discovered, which is incidentally where the word “fluorescence” comes from. Fluorescence – the emittance of that strange otherworldly light – is caused by the dancing of electrons within the mineral’s atomic structure. As they stomp around to the doef-doef music in their heads, they emit quanta of visible light that is most frequently blue in colour, but can be green, white, red, purple or yellow.
Stay Tuned for Part 2…
You may be bored at work, but you still have to look busy or else your boss will give you the boot. To accommodate this, I have taken the liberty of dividing this post in two. Stay tuned for the second instalment in which we shall intrepidly explore the remaining three most awesome rock minerals!
In the meantime, your homework is to ‘ooh’ and ‘aah’ at this picture…
“Lechuguilla Chandelier Ballroom” (New Mexico) by Dave Bunnell. Licensed under CC BY-SA 2.5 via Wikimedia Commons. Giant otherworldly fingers of glittering gypsum crystal formations reach down from the cave ceiling.