Crystal Shapes

We're going to move on now to the crystalline structures of gemstones. This will help you gain an even better perspective of gemstone characteristics. Most mineral gemstones are crystalline, with their atoms arranged in regular and symmetrical patterns, kind of like a lattice. There are some that are amorphous, with no or only a weak crystal structure.There can be single crystals or many in a group in crystalline minerals. Polycrystalline minerals are usually made up of many small crystals. In cryptocrystalline minerals, they are too small to see without using a microscope. 

Crystalline minerals are made up of a number of flat surfaces, or faces. The way these faces are oriented defines the overall shape, which is known as the habit. Some minerals have a single, characteristic habit (such as pyramidal or prismatic). There are others that can have several. A lump of crystalline mineral without a definitive habit is called massive. Amorphous gemstones (like tektites and obsidian) have an irregular shape. Let's take a look at examples of common habits:

Amorphous Amber sample

Pyramidal Topaz sample

Acicular Millerite sample

Prismatic Linarite sample

Gemstone massive sample

Dendritic sample

And a quick word about twinning. As we all know, natural crystals are very rarely perfect. Their growth is influenced by all kinds of external factors, such as temperature, pressure, space, and the medium in which they grow. Twinning is an irregularity that can occur when the internal structure of the crystal is repeated. But of course, twins can grow together in any number of different ways. Take a look below:

Topaz twinned with Albite

 

 Okay, well that's enough for this go-round! Next time we're going to cover crystal systems. That's where the Geometry should come in handy. Be prepared to think three dimensionally, haha! You'll need to be able to envision multiple, symmetrical sides. Just letting you know ahead of time! Anyways, thanks for reading, and until next time.




 

The Physical Properties of Gemstones

Now we're going to talk about what makes up a gemstone. The physical properties of gemstones are their hardness, their specific gravity or density, and the way the break, or "cleave".  These properties all depend on chemical bonding and the atomic structure inside the stone. Take for example diamond and graphite. Diamond is the hardest known natural material, and graphite is one of the softest, yet both are composed of carbon. It's the way in which the carbon atoms are bonded together in a diamond that gives it greater resilience and hardness. 

Hardness: One of the key quality of a gemstone, hardness can be measured by how well a stone resists scratching. Every stone can be tested and classified using the Mohs Scale of Hardness, which goes in increments from one to ten. Check out the scale I have below.

Mohs Scale of Hardness

 Intervals between numbers on the scale are not equal, particularly between nine and ten. Keep this in mind though: Hardness testing is destructive, so it should only be used when all other tests fail.


I'll talk about the Knoop Scale very quickly and make it as simple as possible. Remember when I said not all numbers on the Mohs scale are equal, especially between nine and ten? This is best shown with a Knoop Scale. Look at it below.

Knoop Scale

This scale shows the indentation caused by a diamond point when it meets the surface of a mineral. Those ten stages displayed correspond with the Mohs scale. There. Hopefully that makes sense!

Specific Gravity: The specific gravity (SG) of a gem is just another indication of its density. It's calculated by comparing the stone's weight with the weight of an equal volume of water. The greater a stone's specific gravity, the heavier it feels. 

Cleavage and Fracture: Gemstones break in one of two ways. Either they cleave or they fracture. Which way they break is depends on the internal atomic structure of the stone. Gems the cleave tend to do so along planes of weak atomic bonding (cleavage planes). These planes are usually parallel, perpendicular, or diagonal to the faces of the crystal (as both are related to the stone's atomic structure). Gemstones may have one or more directions of cleavage which can be defined as perfect (almost perfectly smooth), distinct or indistinct.

When a gemstone breaks along a surface that is not related to its internal atomic structure, that's when it's referred to as a fracture. Generally, fracture surfaces are uneven. Each one has it's own descriptive name. Check them out with the pictures I've provided below. They'll give you a better idea what I'm talking about.

Perfect cleavage in Calcite

Distinct cleavage in Epidote

Indistinct cleavage in Aquamarine

Uneven fracture in Dumortierite

Conchoidal fracture in Obsidian

Hackly fracture in a gold specimen

Splintery fracture in Nephrite

Okay, well that covers the physical properties part of this journey. I did my best to keep it brief and as easily understandable as possible. I know these more scientific and technical parts get a little tedious, but if you really stop to think about it (and if you're in love with gems the way I am), the science behind the gemstone is what makes it so beautiful. Without this particular knowledge, we couldn't fully understand and appreciate gemstones for the incredible miracles of nature they are. So hang tight, we're moving right along. Next time we'll go over the crystalline shapes of gemstones. If you remember anything about Geometry, that section will make sense. So thanks for reading, and until next time!

Locations, Locations, Locations...

We're moving right along! Let's talk today about where gemstones can be found. There are certain places on the map that are huge players in the gemstone market. There are some gemstone minerals (Quartz for example) that can be found just about anywhere around the world. Others, like precious diamonds and emeralds, are far more rare. This is because of the particular, unusual geological conditions required for their formation. Keep this in mind though: Just because a mineral may be found around the world, doesn't mean it's all gem quality material. Only a minute portion may be the good stuff. So it makes sense that the main gem locations of the world are where gem quality materials show up enough to go into production.

Thanks to a pretty nifty site called JewelInfo4u.com, I was able to procure a world gemstone map, which is a great way to get a general idea what major gems come from which major areas. There are, of course, many other gems that can be found in many other places, but this map covers the big players and their countries of origin.

World Gemstone Map, Courtesy of JewelInfo4u.com

Pretty interesting, isn't it? And just think... these listed gems and locations are only a small portion of what's available out there. Most people think gemstones and baubles like rings and bracelets pop into their heads, or images of Arabian Knights and the cave of the Forty Thieves, laden with gems and precious things. Some think on gemstones in a more modern, practical way, and others more romantically. Gemstone collectors and those with professional passions for gemstones - loose and set - have always seen the adventure in the stones they obsess over. Everything about them, from the basic (and advanced) science beneath the shimmering facets, to staying up to date and current with all that happens in the world of gems. Just like any other hobby, passion, obsession, whatever you choose to call it... there is so much to know and learn and above all - love.


That was all a really long-winded way of saying to you all, "Isn't this amazing?! Just this basic information?! Who knew there were Emeralds in the hills of North Carolina?!" Or something along those lines. I smile a little at myself, sitting here trying not to go off on a million different tangents about how fantastic the entire world of gemstones is. What I'm trying to do here is introduce, not force-feed. My goal is not to convert, but rather to give you all a taste. Hopefully your appetite is growing, and you're getting hungrier for more. And let me tell you my friends, you will indeed be satisfied, for there is so much more yet to come! Until next time, and thanks for reading.

Origins and Formations, Part II

Okay, back again tonight to discuss an essential subject: How gemstones are formed. All gems that have a mineral origin are found in rocks, or "gem gravels" that come from those rocks. As you may or may not remember from middle school Earth Science classes, all rocks are made up of one or more minerals and can basically be divided into three main "types". The formation of these types, by name igneous, sedimentary, or metamorphic, is a continuous process. The term "rock cycle" is used to describe this process. Take a look below at the chart so you can get a better idea of what that process includes: 

The Rock Cycle

 Gem-quality minerals within these rocks can sometimes be easily accessible at the surface of the Earth, or they can be buried deep beneath it. The ones separated from their host rock by the process of erosion are carried through rivers out to lakes or the sea. 

Now Let's go through the different varieties of rocks. Although a little on the tedious side, this information is crucial to understanding gemstone formation and, later on, gemstones themselves. Igneous Rocks: These rocks have solidified from molten rock from deep beneath the Earth's surface. Some of these, called extrusive igneous rocks, are thrown from volcanoes in the form of lava, volcanic bombs and ash. Intrusive igneous rocks are ones that solidify beneath the surface. Here's the essential idea: The slower a rock cools and solidifies, the larger the crystals... and the gemstones inside those crystals. Many of the larger gemstone crystals out there form in pegmatite, a form of intrusive igneous rock. Metamorphic Rocks: These rocks are either igneous or sedimentary rocks, changed by the heat and pressure from inside the Earth, forming new rocks with new minerals. When this happens, sometimes gemstones can grow inside of them. Take Garnets for example. They can form within micha schists, rocks which were once mudstone and clays. And Marble can contain rubies because it's formed from limestone that has been under crazy heat and pressure. Sedimentary Rocks: These are formed by the accumulation of rock fragments made by the process of weathering. After a time, the fragments settle and harden into rock again. These rocks are usually laid down in layers, and these layers are sometimes treasured as a feature in decorative stones. Look at Australian Opal. It occurs in sedimentary rocks. Turquoise occurs as veins in rocks such as shale, and halite and gypsum are both sedimentary. Organic Gems: These, as we've talked about before, come from plants and animals. Pearls, as most people know, form around foreign bodies that made their way into marine or freshwater shellfish. Cultured pearls, on the other hand, are created artificially in big fisheries, usually in shallow waters like the ones off the coasts of China and Japan. Shells can be treated as gems too, and can come from different creatures like snails, turtles, and animals ranging from the ocean to freshwater to land. Like coral for example. It's made from the skeletons of coral polyps, tiny little marine animals. And think about bone, or ivory from the teeth or tusks of mammals. They can come from living animals, or from fossils that are thousands of years old. Then there's Amber, which is fossilized tree resin. You can collect it from soft sediments or straight from the sea. Finally, Jet is fossilized wood, found in certain sedimentary rocks.

Igneous Rock

Metamorphic Rock

Sedimentary Rock

Amber - Example of Organic Gem

Well, that's enough for one post! Hopefully I kept it as light a fare as possible for you all. Next we'll be discussing basic gemstone locations, and from there physical properties. Until next time, and thanks for reading!

 

Origins and Formations, Part I

Let's talk a bit about what gemstones are and how they are formed. I'm breaking it up into two parts, as I'm running short on time tonight. But don't worry, we'll get it all covered! I'll go quickly and yet try to keep all of this stuff as interesting as possible. I mean, it's not that it's boring or anything, but as I'm sure anyone can figure out for themselves, it gets tedious at times.

Gems are basically minerals that have been fashioned for personal use or for wearing around.The Golden Rule is they must be beautiful, rare, and durable. Most are natural, inorganic materials with a certain chemical makeup and a regular internal structure. Some gems come from plants or animals and are called organics (amber, pearl, etc). There are also synthetics, which although not natural in origin have physical properties similar to natural gems. Most synthetics are cut to look like natural gems.

Pretty much every cut stone begins in crystalline form stuck in the host rock, or matrix (we discussed this earlier). At this stage, the stone is called a rough. Many of these you could just stick on a shelf to display to all just the way they are, they are so beautiful! Most go on to be faceted and polished. 

Go ahead and take a look below at the possible progression of an emerald.

Emerald Crystals in the Host Stone (Matrix)

Natural Emerald Crystal

Polished Emerald Stones

Emerald Cabochon

Faceted Emerald

That wraps up Part I, and next time I'll post some basic info on how gemstones are formed. You know, those scientific details that have some of you out there drooling over the idea of igneous rocks. Thanks for tuning in again!

A Bit of Introduction

Let's talk about the basics of gemstones. First question first: What is a gemstone? There are over 3,000 different minerals, but only about 50 are commonly seen as gemstones. Others are too soft or easily scratched, so they aren't really suitable for wear. The number of minerals used commonly as gemstones constantly changes as new sources and varieties are found and, of course, fashions change.

To be called a gemstone, minerals - or occasionally organic materials - must be considered beautiful, most especially in regards to their color. It must also be durable enough to go through use and handling without becoming scratched or damaged. Lastly, rarity is ultra important. A gemstone's scarcity is what gives it a greater market value.

Diamond, king of the "Big Five"

Sapphire

 

Emerald

Pearl

Pictured here are the "Big Five", the five major, most highly prized gemstones on the market. All except pearl have a certain cut that displays their best qualities.

Ruby

Okay, next up: The science behind the gems. All gems are absolutely fascinating scientifically, at least in my opinion (there may be those who think differently, but for argument's sake, let's just go with the idea that everyone agrees with me). Gemologists make a thorough study of each stone that they acquire, both as it occurs out in nature and after both the cutting and polishing. Throughout my posts, I'm going to try my best to find images of the gems I discuss in their rough, natural states. In most cases, pictures of the matrix (the host rock) are hard to come by. I will also, of course, try to include as many pictures of each species of gemstone after it has been cut, polished, or carved as possible. I'm hoping I can nab a microphotograph here and there so as to display the internal structures of stones. When getting in that close, that's where the REAL fun begins, as does all the detective work. But we'll go into all that at another time. Right now, let's talk a little about why gemstones are fun for just about anyone.

  

Throughout time, gemstones have symbolized wealth and power, we all know that. Everything from crowns to costly clothing that have adorned the holders of wealth and supremacy have been dripping with jewels. But gems are not just for rich people or scientifically inclined individuals. They can be loved and enjoyed by anyone, from the amateur collectors out there to professional jewelers, and right down to those simply obsessed with the history of gemstones. For most people though, the real kicker is actually owning their own gemstones. Most of us can't afford the hugely expensive stones on the charts, but anyone - even third graders - can grab up a few minerals that (even if not gem quality) are beautiful to the eye and satisfying to the soul. And who says you have to spend tons of money on it all? There's amber on the beaches, topazes in the dirt, and affordable pieces of jewelry packed with lovely gemstones all over the world. You don't believe me, search eBay!! Just because you want to collect and/or enjoy gemstones does NOT mean you have to be a rich scientist. Trust me, I'm neither, and yet here I am. It doesn't matter how modest your collection may be, it's all about the fascination and enjoyment you get from each and every little piece. If that's not how you feel about gemstones, I'd venture to say you've got the wrong hobby!

Next time, I'll discuss in depth what exactly it means to be a gemstone, as well as how they are formed. We'll continue on from there into the last of the "scientific details", and then launch right into identification. Around and about there will be personal stories, discussions with others, videos, etc. And of course, I will - from time to time - make purchase suggestions, geared mostly towards those just starting out with their collections. I gained incredibly valuable information from many sources when I first started out, but it wasn't until someone very experienced sat me down and told me everything I would need and why I needed it that I really felt like my wings were finally opening. So hopefully I can pass that information on to others so many more gem collections can start sprouting up like dandelions all over the world! A lofty goal, but hey, I dream big :) Thanks for reading, and until next time! 

And Then There Was an Amethyst...

I suppose the best place to start all of this is at the beginning. I was in third grade. My teacher's name was Mrs. Harris. I happened to think she was the bees knees. She had this wonderful habit of taking us on fantastic and whimsical field trips, much like a Mary Poppins of sorts. One day she took us on a day trip to a place called "Gems in the Sand", this little pokey "mining town" out in the middle of nowhere. Of course, to a third grade girl with a wild imagination, just getting out there in the fresh air and parading around the gift shop was enough. But we got to do something rather special right before we left. The man who ran this place had set up a water wheel that pumped water at a slow but steady current down a large channel, separated on each side my mesh wire. It was several yards in length and wide enough to fit one person on each side. It was a wonderful set-up, and our entire class was completely enthralled. We each had brought five dollars as per the instructions on the permission slips sent home, and they paid for a gallon bucket stuffed full of packed sand. We each were handed brightly colored plastic sand shovels and a wooden sifting tray. The point was to scoop little bits of sand out of the bucket into the sifter, and let the soft water current run over it all. While doing so, the sand would melt away to reveal stones of all shapes, sizes, colors and kinds. Most were little hunks of red jasper and occasionally some turquoise. But I must have had a gem collecting angel by my side that day, because the very first thing I came across was a shiny, glittering, oval-shaped stone in the most beautiful violet hue I'd ever seen. I had always enjoyed learning about rocks and such up until that point, so I figured what I had found was just some purplish quartz. But something about how the stone glittered and made me want to rub my fingers around it made me consider taking it to the man who owned the place, who was patiently watching over all of us grubby little elementary school kids from the front of the water wheel. I handed it to him, asking politely what I may have found. He turned it around in his hand, and told me with a smile he was pretty sure I had found an amethyst. I was amazed! I knew about amethyst and had read about it before, and I was so excited! I found a bunch of other little things here and there that day, but I treasured my gemstone find above all the rest. I remember Mrs. Harris gave me a plastic baggie from her purse for me to carry it home in, and I couldn't help but shove the baggie into my poor mother's face while screaming at the top of my lungs, "I got an amethyst!" when she picked me up from school. 

Looking back on it now, I know for a fact that this was the event that started my life-long obsession with all gemstones. I remember how hungry I became just for basic knowledge of all gemstones, and how I fed it with book after book after book. I discovered that there was not only an entire world of beauty and history behind each and every stone, but some incredible science that - for once in my life - didn't bore me to tears! It was like discovering a whole different world, full of pretty, sparkly things that never quit. I couldn't stop obsessing, though the passion did die off a bit during high school. All of a sudden during that time, the term "cleavage" took on a whole new meaning. And to be honest, gemstones were the last thing on my mind, as we all know... and remember.

I repressed the urge to continue my obsession when I was dragged off to a traditional four year university by my father (God bless him, he would have had a literal cow if I had told him I wanted to learn how to play with rocks for a living). It only truly resurfaced after I was married and had started a family of my own, and my life started to pan out the way I wanted it to. I started becoming hungry for even more knowledge, and so I made a running leap into the deep end and started treading water fast. I bought everything I could get my hands on education-wise, and spent hours upon hours with notebooks and highlighters. Since it's a practice I still carry on today, I won't knock it. Anyone who collects gemstones will tell you the same thing. There's this insatiable need to know everything humanly possible about a certain gem before adding it to the collection, and the need to control the whole process is a trait all gemstone lovers share. Call us OCD, call us crazy, whatever. To each their own. And we choose the way of the sparklies.

So the long story short (too late), I have become a true gemstone lover and collector, and the knowledge I have acquired in the many years since that first amethyst has served me well. I continue to learn, and usually I pass on my information to captive audiences... even if they aren't even really listening to me. You know your husband is tuning you out when he starts snoring whilst you ponder the wonders of pleochroismsomeone's thoughts and experiences through a basic blog like this one when I was younger and first starting out, I would have absolutely soaked it up and used it for great good in my own personal journey. I wanted to give someone out there - even if it's just one person - a chance at that very thing. You know, just lay it all out from beginning to end, with some laughs thrown in to keep the sterile stereotype of the gem scholar from sneaking in. I'll talk more about that later... I'm so looking forward to sharing all I know and love with anyone and everyone who's willing and wanting to listen... or read rather. I hope all who stumble upon my corner of the Internet universe find a great deal of concise, digestible information, and enjoy the hilarious antics that inevitably follow me, my toddler, and my gemstones. Yes, there's a two year old involved...

So in the beginning, there was an amethyst. And I have yet to find a quitting point. Here's to the hope that we will enjoy all of the wonderful things the world of gemstones has to offer, from the scientific to the spiritual and beyond. I will do my best to make this an awesome experience for us all, and my sincerest hope is that you gain from me even the smallest something, even if it's just a moment of laughter. Until next time!