Learn about Natural Gemstones: Sapphires, Rubies & Emeralds

 Ring

Gemstones come in every color and shade under the sun. Through time, a few of these gemstones have become considered precious gemstones through their color, beauty, rarity and durability. We are passionate about colored gemstones and a great deal of our jewelry includes natural colored gemstones. We also understand that with so many options, choosing a gemstone can be overwhelming, so we have put this guide together to help you when choosing to buy a colored gemstone.


General features of gemstones

Some features of gemstones are the same regardless of whether the gemstone is a sapphire, a ruby or an emerald and so firstly we will look at the aspects of jewelry gemstones which are universal to all gemstone types:

 

Color

The color of a gemstone is determined by how it absorbs and reflects light energy. The different materials and impurities which make up gemstones each absorb and reflect light differently which is why each individual gemstone type is a different color.


Why gemstones are colored

In some gemstones, the color is caused by an essential component of the gemstone meaning the gemstones only occur in that color. An example of this is peridot, the composition of which includes iron sulfide with the iron component responsible for creating the vivid green color in the gems.

 

In some other gemstones, the color is caused by impurities in the gemstone material and so these gemstone can occur in different colors created by different impurities. An example of this is sapphires which can be found in colors ranging from pale yellow to deep blue. Blue sapphires are caused by iron and titanium impurities, whereas yellow and green sapphires are caused by iron impurities alone.


How to describe color gemstones

When the color of gemstones is described, it is usually referred to by three distinct terms: hue, saturation and tone:

Hue is the basic color of the gemstone.

Saturation, which is sometimes called color purity or intensity, means the vividness, brightness or colorfulness of the hue of the gemstone.

Tone is the amount of color and covers the range of lightness to darkness of the hue.

The most highly prized gemstones are often those with a vivid and pure, strong toned, hue.

 

Cut

The cut of a gemstone refers to two aspects of the gemstone. The first is how well the gemstone has been cut to enhance the shine or sparkle and color of the gemstone. The second relates to the shape into which the gemstone has been cut.


Cabochon Cut

Colored gemstones are sometimes cut using a style called a cabochon cut which means they are given a flat base and a smooth domed upper surface. This type of cut is favored for color gemstones which are opaque, for example turquoise; those which are patterned, for example agate, or those that are heavily include such as star sapphires, which are sapphires included with rutile which, when cut, shows as a glittering six point star.


Faceted Cut

Colored gemstones, particularly transparent colored gemstones, are more commonly cut as faceted gemstones. There are two main types of facet which can be used, namely brilliant cut facets, where each facet is a triangle or a kite shape, or step cut facets where the facets are cut parallel to each other. In some cases, only brilliant cut facets or step cut facets are used however some gemstones are also mixed cut stones, with a mixture of brilliant cut facets and step cut facets used.


Cut Gemstone Shapes

The most common modern cut gemstone shapes are:

 

Shapes

 

Carat

A carat is a unit of weight measurement which is used when determining the weight of gemstones and diamonds. One carat equals 200mg. A carat can also be sub-divided into 100 points, so 1 carat = 100 points. Larger gemstones are generally much rarer than smaller gemstones so the price of gemstones typically increase as the carat weight increases.

 

As different gemstones are made up from different materials, which differ in density, the size of a gemstone of a particular carat weight can vary between different gemstone types. Therefore, two gemstones that appear to be the same size may actually have very different carat weights. For instance, a sapphire is more dense than a diamond, so a one-carat sapphire will look smaller than a one-carat diamond. Let's use 6mm round shaped stones as examples :


Carat


Clarity

The clarity of a gemstone is a measure of any flaws found within the cut gemstone. Surface flaws are called blemishes and internal flaws are called inclusions. The flaws may include cracks or fissures, bubbles of gas or other materials or minerals caught within the gemstone as it formed.

 

For diamonds, the clarity of the cut stone is very important. However, for colored gemstones, the clarity of the gemstone isn't such an important factor. For example, whilst a very clear rich blue or pink sapphire may be very desirable, a blue sapphire with many rutile inclusion (also known as silks), which create a cats eye effect, can be every bit as desirable and valuable.

Furthermore, a beautiful bright cornflower blue sapphire which has a few inclusions may be worth much more than a drab grey blue sapphire which has no inclusions. In addition, some very beautiful and valuable colored gemstones, such as pearls or turquoise, are completely opaque. Therefore, for color gemstones, the clarity of the gemstone is a factor which is only relatively important.

 

Gemstone Hardness

Gemstones are rated in hardness using a scale called Moh's scale where 1 is the softest stone and 10 is the hardest. Diamonds are the only gemstones which have a hardness of 10 with all other gemstones being softer than diamonds. The different hardness of color gemstones means that there are some which are more suited to certain types of jewelry than others.

 

For example, sapphires and rubies have a hardness of 9 and so, similarly to diamonds, these are very hard stones. This means that sapphires and rubies are perfect for use in a ring as they do not scratch easily and can withstand daily wear and tear. However, a gemstone such as apatite, a beautiful clear asparagus green color gemstone, which has a hardness of 5, is relatively soft and could be scratched easily by a steel kitchen knife for example. This means that apatite is far too soft for use in a ring, as it would easily be damaged but if used in earring or a pendant, it would look stunning.

 

Therefore when choosing color gemstone jewelry, it is worth considering what type of wear the jewelry will get and whether the gemstone is hard enough to withstand that type of wear.

 

 

 Hardness

 

 

Precious Gemstones: Sapphires, Rubies and Emeralds

Sapphires, Rubies, and Emeralds are the most desirable precious gemstones, and are commonly used in fine jewelry.


 Sapphire   RubyEmerald


Sapphire Education

 Sapphire Education


Blue is not the only color!

Sapphires are formed of a mineral called Corundum which is the crystalline form of aluminum oxide and when you think of sapphires, it is likely that you automatically think of the color blue. However, sapphires are actually found in a range of colors. Our Wedding Ring specializes in blue sapphires and pink sapphires in particular but sapphires ranging from yellow and green though to purple can also be found. Whilst all of these colors are still called sapphires, when corundum is found in a red form, it is called a ruby.


Sources of Sapphires

Sapphires are mined all over the world with mines found in India, Sri Lanka (Ceylon), Burma, Australia, Brazil, Thailand, Vietnam, Madagascar, Africa and even in the USA. Unfortunately, as with many gemstones, the sapphires which are considered the most valuable blue sapphires are found in the war torn region of Kashmir on the Indian border with Pakistan. Other sources of blue sapphires are Sri Lanka (previously Ceylon) as well as Australia and Thailand. Many pink and yellow sapphires are found in Madagascar with purple sapphires typically coming from Brazil.


The Value of Sapphires

As with diamonds, the value of a sapphire is dependent upon the 4C's of cut, clarity, color and carat.Sapphires are rare gemstones, much rarer than diamonds, and this too can add a premium to the value of a high quality sapphire. In the main, the color of the gemstone, even taking into account heat treatment to improve color, is determined by the location at which the sapphire was mined. To this end, the blue sapphires from some areas, such as Kashmir and Ceylon are considered particularly beautiful and are highly valued. High quality deep pink sapphires are also considered very valuable.


Durability of Sapphires

After diamonds, sapphires are amongst the hardest gemstones known to man. Corundum is 9 on the Moh's scale of hardness and this means that sapphires can be very durable hard wearing stones. As diamonds are harder than sapphires they can damage sapphires. Other sapphires and rubies can also damage sapphires, therefore as with all jewelry, it makes sense to store sapphire jewelry wrapped individually in a soft cloth.


History of Sapphires

Sapphires have been very popular and mystical gemstones throughout the ages. The Persians believed the blue of the sky was caused by the reflection from sapphires which supported the earth and King Solomon's seal was allegedly made from a sapphire. The association of sapphires with royalty continues to this day, with Prince William having proposed to Kate Middleton with his mother's iconic sapphire engagement ring. Sapphires symbolize sincerity and faithfulness. In addition, sapphires are the birthstone for September and, in the US, is associated with the 45th wedding anniversary.


Enhancement of Sapphires

Within the gemstone industry, it is acceptable and common practice for mined sapphires to be heat treated to improve their color and clarity. Untreated sapphires can occasionally be completely clear, however more commonly, they have multiple small inclusions often called silk bands. Whilst in some cases these inclusions can result in a beautiful gemstone, more commonly, the gemstone is considered more beautiful without the silk bands. As the silk bands are a result of the gemstone having cooled to quickly during its formation, by heat treating the sapphire it can be irreversibly clarified making it more desirable. The sapphire is still considered natural as no chemicals have been added to the gemstone. The majority of commercial sapphires have been heat treated in this way. In addition, by careful multiple heat treatment, the color of the sapphire may be made clearer or brighter, this is much less common however can result in the beautiful pale Ceylon Blue sapphires which are very expensive.

 Sapphire Enhancement

All of the sapphires used by us are Natural Sapphires and whilst the majority have been heat treated, some un-heated sapphires are available. However, due to the rarity of high quality un-heated sapphires, they are substantially much more expensive than those which have been subjected to heat treatment.



Care and cleaning of Sapphires

The weakest point of a sapphire is at the edge or point of the cut stone where any impact could cause the sapphire to chip or shatter, for this reason, it is best to remove your sapphire jewelry when doing rough work

 

Sapphires can easily be scratched or scraped by the edge or point of another sapphire, as well as by rubies and diamonds. To minimize the risk of this happening, always store your sapphire jewelry wrapped individually in soft cloth. After each time you wear your sapphire jewelry, use a soft jewelry cleaning cloth to remove the accumulated dirt before you putting it back in your jewelry box. All of our jewelry is supplied with a super-hi-microfibre jewelry cleaner cloth to help you do just this.

 

Give your sapphire jewelry a regular clean at home in a bowl of warm water with a few drops of washing up liquid. Soak the jewelry in the water for around 30 minutes, then using a soft brush, clean around the gemstone. Once clean, removed the jewelry and dry it using a soft cloth.

 


 

Ruby Education

 Ruby Education

Rubies are formed of a mineral called Corundum which is the crystalline form of aluminum oxide. This is the same mineral which forms sapphires, however only when the mineral is colored red, due to the presence of chromium as an impurity in the stone, is it considered to be a ruby. As a result, rubies are very rare, and very valuable, gemstones.


Sources of Rubies

Ruby mines can be found dotted around the world with the most well known mines in Burma (Myanmar) where the most valuable, pigeon blood red rubies, have historically been found however mines in Kenya have also been the source of some magnificent quality rubies. Ruby mines are also found in Pakistan, Sri Lanka (formerly Ceylon), Thailand, Cambodia, Vietnam, Afghanistan, Mozambique and even in the USA.


The Value of Rubies

As with diamonds, the value of a ruby is dependent upon the 4C's of cut, clarity, color and carat.Rubies are extremely rare gemstones, very much rarer than diamonds, and this places a high value on a top quality ruby. In the main, the color of the gemstone, even taking into account heat treatment to improve color, is determined by the location at which the ruby was mined. The rubies termed pigeon blood red rubies, which traditionally came from Burma, are considered particularly beautiful and are highly valued. However strong, vivid, fire red rubies from any region are considered very valuable.


Durability of Rubies

After diamonds, rubies, along with sapphires, are amongst the hardest gemstones known to man. Corundum is 9 on the Moh's scale of hardness and this means that sapphires can be very durable hard wearing stones. As diamonds are harder than sapphires they can damage rubies. Other rubies and sapphires can also damage rubies, therefore as with all jewelry, it makes sense to store ruby jewelry wrapped individually in a soft cloth.


History of Rubies

 Ruby History

Rubies have long been very sought after gemstones and have, for thousands of years, been one of the most valuable gemstones. They have long been attributed mystical qualities with ancient Burmese people believing they rendered a person invincible if they were inserted beneath the skin. It was also believed that rubies could predict impending danger by becoming darker. Rubies symbolize love. In addition, rubies are the birthstone for July and, in the US, is associated with the 40th wedding anniversary.



Enhancement of Rubies

Within the gemstone industry, it is acceptable and common practice for mined rubies to be heat treated to improve their color and clarity. Untreated rubies can occasionally be completely clear, however more commonly, they have multiple small inclusions often called silk bands. Whilst in some cases these inclusions can result in a beautiful gemstone, more commonly, the gemstone is considered more beautiful without the silk bands. As the silk bands are a result of the gemstone having cooled to quickly during its formation, by heat treating the ruby it can be irreversibly clarified and the color improved, making it more desirable. The ruby is still considered natural as no chemicals have been added to the gemstone. The majority of commercial rubies have been heat treated in this way.

 

All of the rubies used by us are Natural Rubies with the majority having been heat treated to improve clarity and color. , Some un-heated rubies are available. However, due to the rarity of high quality un-heated rubies, they are substantially much more expensive than those which have been subjected to heat treatment.

Emerald Education

 Emerald Education

Emeralds are formed of a mineral called beryl. Pure beryl is completely clear, however beryl is the same mineral which forms other gemstones such as aquamarine, helidor and morganite gemstones. The coloring of beryl is determined by impurities with the gemstone however, only when the impurity is chromium, is the grass green beryl called emerald formed. As a result,Emeralds are very rare and very valuable gemstones.


Sources of Emeralds

Emerald mines can be found around the world with the most ancient mines in Egypt where emeralds have been being mined for over 3000 years. Mines still exist in Egypt as well as other locations in Africa including South Africa, Madagascar and Zambia. Emerald mines are also found in Columbia, Brazil, Russia with some emerald deposits even found in the USA.


The Value of Emeralds

As with diamonds, the value of an emerald is dependent upon the 4C's of cut, clarity, color and carat. Emeralds are rarer than diamonds and large, clear vivid emeralds are even rarer, making these extremely valuable gemstones. In the main, the emeralds which are an intense grass green color are the most desirable and valuable however the nature of these gemstones mean that colors ranging from a pale green through to a deep rich green can also be extremely beautiful and valuable. As emeralds are type III gemstones, they naturally have many inclusions although these inclusions do not always detract from the value of an emerald.


Durability of Emeralds

Emeralds are an 8 on the Moh's scale of hardness and this means that are reasonably durable. However, the inclusions found in emeralds make them vulnerable to heat damage and extreme changes in temperature may cause them to break as can knocks or bumps. Also, given that many emeralds are oiled, exposure to harsh detergents or chemicals can dilute or dissolve the oil which has soaked into the emerald reducing their clarity and color. As diamonds, sapphires and rubies are harder than emeralds they can scratch or chip emeralds. Other emeralds can also damage emeralds, therefore as with all jewelry, it makes sense to store emerald jewelry wrapped individually in a soft cloth.


History of Emeralds

Emeralds have been mined for over 3000 years and were highly prized gemstones amongst the ancient Egyptians with Cleopatra known to have been a keen collector of emeralds. They have long been attributed with magical qualities such as the ability to heal the heart, improve the memory or increase fertility. Emeralds symbolize faithfulness. In addition, emeralds are the birthstone for May and, in the US, is associated with the 55h wedding anniversary.


Enhancement of Emeralds

As emeralds are type III gemstones, it is common for even very beautiful emeralds to have a great many flaws and inclusions. Within the gemstone industry, it is acceptable and common practice for mined emeralds to be oiled to improve their color and clarity. The process of oiling involves immersing an emerald in oil which seeps into the cracks and fissures which are commonly found in emeralds. This treatment has the effect of improving the clarity of the emerald. It is also not unusual for a green oil to be used to further enhance the color of the emerald.


Care and cleaning of Emeralds 

 

 Emerald Cleaning

As a result of the inclusions in emeralds, whilst reasonable hard, they are vulnerable to breaking or cracking, particularly if bumped. As a result, it is best to remove your emerald jewelry when doing rough work.

 

Emeralds can easily be scratched or scraped by the edge or point of another emerald, as well as by sapphires rubies and diamonds. To minimize the risk of this happening, always store your emerald jewelry wrapped individually in soft cloth. When you remove your emerald jewelry after wear, use a soft jewelry cleaning cloth to remove the accumulated dirt before returning it back to your jewelry box.

 

Give your emerald jewelry a regular clean at home in a bowl of warm water with a few drops of a gentle washing up liquid. As emeralds have inclusions and flaws they are vulnerable to cracking if exposed to large changes in temperature, so make sure that the water you use is warm and not very hot. Also, the oil treatment applied to emeralds can be diluted or dissolved by harsh chemicals, so be carefully only to use gentle detergents. Soak the jewelry in the water for around 30 minutes, then using a soft brush, clean around the gemstone. Once clean, removed the jewelry and dry it using a soft cloth.

 

It is important never to clean emerald jewelry in an ultrasonic cleaner as the inclusions in the emerald leave the gemstone liable to break if ultrasonic vibrations were applied to it.