Ruby – the birthstone of July

 

We’re halfway through the year folks, when did that even happen?! The first half has been so much fun but it’s been speeding by for me and I feel like it really needs to slow down. So much to do / see / enjoy and so little time.

Anyway, let’s steer the focus back to the birthstone for this very summery month – the ruby. You July babes sure are lucky to have this fabulous gemstone as your birthstone!

Ruby jewellery set, the perfect set for a July born babe who likes a touch of feminine pink. All pieces made by Linda Sääv.

The feminine ruby

Rubies for me are the embodiment of femininity in a gemstone. Their hot pink to blood red colour is divine and are loved by women of all ages. Even someone who might not be that in to pink will still get intrigued by a ruby.

I mean if your jaw doesn’t drop from the sight of the ruby pictured below, you need to get your eyes checked!

Hot pink and glowing little ruby wrapped in flattering 14k rose gold fill wire. Made by Linda Sääv.

Ruby science

The ruby is a pink to red variety of the mineral corundum (aluminium oxide, Al₂O₃) and is a sibling to the other corundum colour varieties named sapphires. In fact, all other gem-quality corundum stones not having a shade of pink or red is called sapphires (read on for the pink sapphire versus ruby debate).

A completely pure corundum is colourless, so rubies get their colour from trace amounts of chromium in the crystal lattice. The more chromium, the stronger the red colour. The chromium can also cause fluorescence, which adds to the glow and intensity of the red colour when viewed under ultraviolet light – even from the ultraviolet light in sunlight.

Top left: colourless corundum crystal. Bottom left: irregularly shaped glowing pink ruby with a hint of orange. Right: raw ruby, loose and in host rock with a hint of purple. The faceted ruby is more red with a hint of pink.

Iron can also be present in the chemical makeup of a ruby. Iron on the other hand can make the rubies darker and less intense in colour. Higher iron content can also mask the red fluorescence.

50 shades of red

Although rubies are defined to be red, they may exhibit a range of secondary hues, including orange, purple, violet and pink (as already seen in the previous photo). Of the three, purple is preferred because it reinforces the red, making it appear richer. However, too much purple and the ruby moves down the quality scale.

50 shades of red. Nah, just kidding, sort of. Even though it might not look like it, all rubies are defined to be red in hue. The pink or purple colouration you see is only caused by their secondary hues.

The ruby hex

Rubies (as all corundum varieties) are part of the trigonal crystal system and most often occur naturally as terminated tabular hexagonal prisms. Imagine two stretched six-sided pyramids attached at their base and you have a rough idea of how a ruby crystal looks like.

Top left: raw ruby crystal showing off its hexagonal shape, it’s also showing off that it’s part of the trigonal system with the triangle on its top. Right: a raw ruby with a faint hexagonal shape. Bottom left: a collection of ruby crystals and clusters (and one blue sapphire).

Rubies are naturally very hard with a hardness of 9 on the Mohs scale of mineral hardness. Only moissanite and diamond are harder, with diamond having a hardness of 10 and moissanite falling somewhere in between corundum and diamond.

Naturally imperfect

When it comes to imperfections, all natural rubies have them. Imperfections include colour impurities and inclusions of rutile needles known as “silk”. It’s the rutile inclusions that make distinguishing natural rubies from synthetics or simulants possible.

Left: rutile needles (golden) on hematite (metallic). Top right: microscope image of a criss cross pattern made by rutile needles in a ruby. Bottom right: Close up of thin rutile needles making the same but faint criss cross pattern seen above.

The rutile inclusions can sometimes cause an optical phenomenon called asterism. An asterism or “star” is a three-point or six-point surface effect that occur when light is reflected off the structurally oriented rutile needle inclusions of the stone in a certain way. These rubies are usually cut into cabochons to properly display the effect. Similarly, rubies can also show chatoyancy, also called the “cat’s eye” effect. In this case, the rutile needle inclusions are actually increasing the value of the ruby.

Two cabochon cut star rubies clearly showing the six-pointed surface effect caused by the silk within.

These days, almost all rubies are treated in some form, with heat treatment being the most common practice. Heat treatment of a ruby improves the colour, removes any purple tinge as well as “silk” which also improves the clarity.

Another treatment is lead glass filling, a treatment where any fractures inside the ruby is filled with lead glass, a treatment that dramatically improves the transparency of the stone.

Untreated rough rubies (left) versus heat treated rough rubies (right).

Ruby vs. pink sapphire

The distinction between ruby and pink sapphire is often made by looking at the colour saturation of the stone. If the saturation isn’t high enough it will be called a pink sapphire and subsequently, if the saturation is above a specific threshold it will be called a ruby. Furthermore, one can argue that for a corundum to be called a ruby, red must be the dominant hue.

However, often, the identification of the dominant hue is difficult and can be debated – it’s not clear and it really is just a matter of personal perception.

Historically though, the word ruby referred to shades of red, which technically included pink.

Four different corundums having the same hue (red), but showing a variation in saturation and tone. Most gem dealers would classify number 3 and 4 as rubies, whereas number 1 would be classified as a pink sapphire. Number 2 walks the line, it’s a ruby to some, while a pink sapphire to others.

The queen of gems

Ruby is the most valuable variety of the corundum mineral species and rubies can in fact command the highest per-carat price of any coloured gemstone.

The quality of a ruby is determined by the same principles as other precious gemstones: colour, cut, clarity and carat weight – all of which affects its value.

For rubies, colour is the most important quality factor. The finest ruby has a pure, vibrant red to slightly purplish red colour –  called “pigeon’s blood” rubies. After colour follows clarity: a clear stone will naturally be more valuable. However, a ruby without any needle-like rutile inclusions may indicate that the stone has been treated, which lowers its value.

Rubies in the wild

Rubies are most often found in marble. The most renowned rubies, like those from Myanmar, the Himalayas and northern Vietnam, typically form in marble.

Here they’re found in layers that are distributed irregularly within the surrounding marble. The marble is formed from existing limestone deposits during metamorphic (rock-altering) processes.

Marble is a type of rock with low iron content, which means rubies formed in marble are more likely to have an intense red colour due to the lack of iron.

Rubies in marble showing off their more vivid colouration.

Rubies can also be found in basalt rocks. Basalt has high iron content which means that rubies originating in these rocks can have higher iron content as well. And as you’ve already read, the addition of iron can cause the rubies to be darker and less intense in colour (see picture below), as well as mask the red fluorescence, eliminating that extra glow of red colour seen in rubies originating from marbles.

Another type of ruby is found in amphibolite and the most renowned ones originate from Mozambique. These rubies are quite fascinating due to their range in iron content, from as high as rubies found in basalts to as low as rubies found in marbles. This of course causes a wide range of colours for rubies mined in this area.

Top left: rubies in amphibolite. Right: rubies with high iron content.Bottom left: rubies with low  iron content.

So which ruby is your favourite? The more red ones or the more pink ones? I for one is a sucker for those hot pink fuchsia coloured ones!

. . . . .

I hope this blog post was interesting and fun to read and that you now have a little better understanding and appreciation of this beautiful queen of a gemstone!

I’ll be back in a couple of weeks with something completely different, so until then, have a wonderful time wherever you are!

♥ Linda

The January birthstone – garnet

So, it’s been a few weeks since my last blog post. I wanted to publish this particular one a little earlier but life got in the way and I definitely under estimated how difficult it would be for me to try to explain all of these science terms in an easy and understandable way, haha! But hey, it’s still January so as I see it, I made it just in time!

Garnet and 14k gold fill jewellery from my birthstone collection.

Anyways, this is the first post of what will be a monthly series about birthstones. Each month I will write a post dedicated to its respective birthstone(s) and give you facts about its different properties (colour, shape, hardness), where it can be found and other interesting facts.

I’m going to let my inner geology nerd shine through in these posts which means they will be jam packed with science! But don’t worry I will try and make it fun, interesting and easy for you. My goal is to make you look at each gemstone in a completely new light.

The glorious garnet

January is of course dedicated to garnets, one of my favourite gemstones due to its beautiful colour diversity, well-developed crystal shapes and it’s geological importance (I’ll come back to that). And also, it’s my birthstone!

 

One of a kind grossular garnet earrings.

 

Garnets have been used as a gemstone since the Bronze Age due to its commonness, beauty and durability. The word garnet can be thought of as a combination of two old words: the 14^th-century English word gernet, which means ‘dark red’, and the Latin word granatus, from granum (‘grain, seed’). The second one is possibly a reference to pomum granatum (pomegranate) whose fruits contain abundant and vivid red seed covers, similar in colour to red garnet crystals.

Garnets me and my husband collected from the gold mine where we first met. These were lying in the granites surrounding the gold ore.

Garnets are common and widespread minerals and can be found all over the world. They are particularly abundant in metamorphic rocks. Metamorphic rocks are rocks that have been altered by high pressure and temperature during for example a collision that forms mountains and turns granites into gneisses or limestones into marbles.

Although garnets form in all of the colours of the rainbow, garnets are often easy to recognize because they are generally found as well-developed crystals in a cubic crystal form, usually occurring as dodecahedrons, trapezohedrons or a combination of the two. I know, I know, you have no clue what those words mean, but the picture below might do the trick.

The many looks of garnets. Top row: dodecahedron (far left) and dodecahedron + trapezohedron combinations. Bottow row: trapezohedron (far right) and trapezohedron + dodecahedron combinations.

The geological importance of garnets

Garnets are more than just beautiful, they play an important role for geologists trying to figure out the genesis of garnet-bearing rocks. Garnets work like record keepers, they store the conditions of which they were formed and altered in. This means that geologists can figure out the temperature and pressure and hence the depth of where a garnet-bearing rock originated. This particular science is called geothermobarometry and was one of my favourite subjects when studying geology! I felt like a detective, figuring out where a particular rock came from and what it had been through since its formation.

The many species of garnets

So, garnets come in a wide variety, can you guess how many garnet species there are? Fifteen! They all follow one general chemical formula: X₃Y₂Si₃O₁₂ , where X can be either calcium, ferrous iron, magnesium or manganese, and Y can be either aluminium, ferric iron, chromium, manganese, silicon, titanium, zirconium or vanadium.

The six largest and most common species are:

• Almandine Fe₃Al₂Si₃O₁₂
• Pyrope Mg₃Al₂Si₃O₁₂
• Spessartine Mn₃Al₂Si₃O₁₂
• Grossular Ca₃Al₂Si₃O₁₂
• Andradite Ca₃Fe₂Si₃O₁₂
• Uvavorite Ca₃Cr₂Si₃O₁₂

Now, this is where it gets complicated, so bear with me as I try to explain. These six garnets are known as end-members and can be divided into two groups. Each group consists of three garnets which simply put mixes with each other during crystallization in what is called solid solution series. This means that almandine (Fe) can mix with both pyrope (Mg) and spessartine (Mn) and grossular (Ca) can mix with both andradite (Fe) and uvavorite (Cr).

With mixing I mean that a garnet is never 100% purely an almandine (100% Fe) for example. There is always a little bit of pyrope (Mg) or spessartine (Mn) mixed in. The name an individual garnet specimen is given is based on the chemical composition and the element (Fe, Mg or Mn) that has the highest percentage.

So, for example, if a garnet is analysed having 80% Fe, 10% Mg and 10% Mn in its composition, that garnet would be classified as an almandine. If a garnet has 60% Mg, 30% Fe and 10% Mn in its composition, it would be classified as a pyrope. And so on. If you take a look at the triangle below though, you see that the mixing has its limits. The yellow area represents the area of all the observed compositions found in garnets. The limitations are due to elemental behaviour during crystallization. I will not go into this further because this is a whole other very complicated topic.

 

The pyralspite garnets solid solution series. Each point of the triangle is dedicated to one of the three end-members and the yellow area represents their mixing area.

How to distinguish between the 6 most common garnets species

Although you can’t be 100% sure of what type of garnet you are looking at without a chemical analysis done in a lab, there are some features you can use to at least narrow down your guesses. Its colour and where you found it can give you some clues. So if you have some garnets laying around at home that you’d like to try and classify, read on! Below follows some short descriptions for each (major) garnet species that might be able to help you out during your detective work.

 

My private collection of garnet crystals. From the left: hessonite, spessartine, spessartine, grossular, demantoid, chrome grossular and tsavorite.

 

Almandine is the most common garnet species and have that deep red colour which garnets most often are associated with. Almandine garnets can be found in granites as well as in metamorphic rocks like mica schists and gneisses.

Pyrope is a fun garnet species because this garnet is an indicator mineral for high-pressure rocks such as diamond-bearing kimberlites, which means that they are used in diamond prospecting! Pyrope normally varies in colour from deep red to black which can make it hard to distinguish from almandine. Rhodolite is a violet-red to pink hued variety of pyrope which chemically is a 2:1 mixture of pyrope and almandine. Colour change or blue garnet is another variety of pyrope which is a mix of pyrope and spessartine. This is the rarest type of garnet. Apart from being found in kimberlites it can also be found in volcanic rocks, which means rocks that have been ejected on to the surface during a volcanic eruption.

Spessartine is most commonly known for its beautiful orange-yellow colour which it gets from the manganese in its composition. Spessartines are mostly more or less orange but they can also be coloured red by substituting the manganese with iron. A vivid bright tangerine orange variety has the aptly name mandarin garnet. Gemstone quality spessartine is rare but is most often found in granite pegmatites.

Grossular garnet can be colourless all the way to black, but it got its name from the green variety which resembled the gooseberry (grossularia) in colour. Other grossular varieties like hessonite are cinnamon brown to orange-red in colour. Tsavorite is a variety which is vividly green in colour. Chrome grossular is a bright green variety, often mistaken for uvavorite. Grossular is commonly found in contact metamorphosed limestones.

Andradite may be red, yellow, brown, green or black. There are three recognized varieties of andradite garnets: topazolite, demantoid and melanite. Topazolite is golden-yellow to olive coloured. Demantoid is yellow-green to emerald-green and has been called the ‘emerald of the Urals’, it is one of the most prized garnet varieties. Melanite crystals are opaque and black. Andradite garnets are commonly found in contact-metamorphosed limestone and in mafic igneous rocks.

Uvavorite is a rather rare garnet species which is bright green in colour. Uvavorite crystals are brittle and almost always too small to be cut as gemstones. Some of the largest crystals come from Outokumpu, Finland. Uvavorite is found in chromium-bearing rocks such as serpentines.

That’s all folks

I hope you enjoyed my first more science-y blog post about garnets. I had a lot of fun writing it but I have to admit, it took me quite a while and I’m still not sure I managed to explain everything good enough. But I had a deadline to stick to and hopefully I will get better at explaining with each birthstone post I write!

If you liked this post or if you have any questions about anything, please leave a comment 🙂

/Linda

Hi there!

For fun I thought I would start with some fast facts about me! So here it goes:

• I’m from and live in Sweden; have you ever heard about the Swedish Dala Horse? Well, I live about 1,5 hours away from where they originated!
• I very very recently turned 32 (happy birthday to me!)
• I studied geology for 5 years and worked in a mine for nearly 2 years before I became…
• …a mother to a wild little boy who turned ONE this New Years Eve!
• I’m married to a red bearded and blond maned man with actual royal blood in his veins.
• I have an unhealthy relationship with volcanoes, minerals and gemstones.
• I started making jewellery in 2014.

So, lets dive into that last bullet point and to how I ended up becoming a jewellery maker.

Volcanoes made me do it!

I guess you could say that my journey into making jewellery all came from my deep love and fascination with volcanoes. I’ve always been intrigued by them, last year I found a volcano painting I made during my pre-teens, case in point. It was my fascination with volcanoes that led me to take an evening course about them, which ended up becoming 5 years worth of geology studies! It was during this time that my love and fascination for minerals and gemstones came to surface.

In 2014, when I made my own and my bridesmaids jewellery for my upcoming wedding I used nothing but real gemstones. I mean, the thought of using glass or acrylic beads didn’t even cross my mind. The years of studying geology were deeply rooted by then. And yes, me and my husband did have a geology themed wedding where we got married at an old mining site close to my hometown.

Creating with real gemstones made me fall in love with jewellery making and gems all over again.

In 2015 I wanted to expand on my skillset so I took my first silversmithing class. And I loved it! To make my very first ring from scratch was such an amazing feeling and I fell in love with the whole process! To create a piece of jewellery from a simple bit of silver thread were so much fun and so satisfying. I felt legit and I knew I wanted to evolve this skill as soon as I set foot in the silversmithing studio.

This year I will take another silversmithing course which will hopefully get me the courage to start soldering and make jewellery for real from my home studio!

Making a name for myself.

I started being serious about jewellery making and try and pursue it as a career in 2016 when I knew I would be out of a job in September of that year and also become a mother in January of 2017.

Before this I mostly made jewellery for myself and for friends and family for fun on my spare time. But in 2016 I made enough jewellery to take part in my first ever fair and I had so much fun! Since then I have attended 4 more shows and this year I hope to attend a few new ones as well.

I opened my Etsy shop September 1st, 2017 and got my first sale on the launch day!

I had hoped to open the shop way earlier that year but after the arrival of our son (who FYI happened to arrive 2 weeks early and thus became one of the last babies to arrive in 2016), my priorities changed and I procrastinated a lot. Mostly due to me being a perfectionist, but also because of negative thoughts that I wasn’t good enough, or creative enough or that people would see me as an imposter. The imposter syndrome is very real from time to time and it really stops me in my tracks.

Anyways, before opening up my shop I did a lot of thinking about what I wanted to make and sell. What I wanted to be known for. I really felt I wanted to make other types of jewellery besides birthstones which back then was what I mainly made. Currently you can find five different collections in my Etsy shop.

All my jewellery have that minimal, clean and simplistic look that I strive for, however I still haven’t really found what I want to be known for. I have a few ideas, but until I reveal them for the world to see, I got to improve on my silversmithing skills. You can’t rush these things.

Finding my creative voice.

One of my long time goals for my business is to find my creative voice, my own style, one that when people see it they instantly knows that that piece is made by me! This means that with time I will narrow down my jewellery assortment and focus my creativity on one style. But don’t worry, before any of this happens I will experiment a lot and evolve my metalsmithing skills. So you can expect to find a lot of new pieces in my Etsy shop this year as I experiment, learn and evolve as a maker!

I hope this was a fun and interesting read, I could have kept going on much longer but I didn’t want to bore you. So I will leave you with some excellent advice from the perspective of a volcano.

Until next time, have a blast!

Happy New Year!

It’s 2018 and I wanted to kickstart this year with launching my very first blog and blog post!

My main purpose with this blog is to make you look at gemstones and jewellery in a new light, because they can be so much more than just pretty adornments. Since I have a degree in geology and I have an unhealthy obsession with rocks and gemstones in general, I will be hitting you with some science from time to time! But don’t worry, I will keep it simple and fun for you. You can also look forward to read about what inspires me, peeks behind the scenes, see works in progress, go through my personal jewellery collection, and so much more.

So are you as excited as I am about this new blog of mine?! I hope so!

But wait a minute, who am I anyway? Stay tuned to find out in my next blog post!