Colored Gemstones Guide

Jessop's is always on the lookout for superior colored gemstones to offer our customers. We purchase them whenever they present themselves, often during yearly buying trips where our jewelers meet with gemstone dealers from around the world, miners and even cutters who sell directly from their sources.

We review thousands and thousands of colored gemstones, spending days with tweezers and loupes, putting our years of experience in noticing nuances in color, brilliance and saturation to work before we bring home our finds and our favorites. We select only the best from sapphires and rubies, emeralds and pearls, along with the loveliest of colored gemstones from tourmalines to Tanzanites to Tsavorite garnets.



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An overview and buyer's guide

Fiery reds, cool and soothing blues, spring-fresh greens. The colored gemstones of the world represent just about every color nature has on offer. And Jessop's has a colored gem for every mood and every occasion.


Choosing a colored gemstone wisely requires thoughtful decisions and the help of trained and experienced gemologists. Jessop's staff of Certified Gemologists and Certified Gemologist Appraisers is ideally equipped to assist you. Understanding the subtle differences that make one ruby fine and another ruby just so-so is our specialty.

A few points to consider before you shop for colored gems

Color may be subjective but when it comes to individual gems there are some fundamental colors we love to see and others which are less fine. There are many gem specimens which are scarce and rare; others gems are relatively plentiful in nature. The rarity and color of a given gem directly influence its availability and its price. A fine Tanzanite could be more expensive and rare than a poor quality sapphire. even though most think of sapphire as being the costlier gem. The nature of certain gemstones can be very pure internally, such as aquamarine. Another gem can be typically included, such as emerald. Therefore the expectation for finding a clean, clear aquamarine would be high and the search for a clear emerald would be much harder.


Keep these characteristic differences in mind as you view gems. Learn the standards for beauty and rarity for the specific gemstone you desire. Be sure to learn from experts like ours at Jessop's.

The Big Three

Ruby, sapphire and emerald are perhaps the 3 best known colored gems. They have adorned Kings and Queens for centuries and were as coveted by the ancients as they are today.

Ruby: Fine quality color should be a rich, vibrant red, not purplish or pinkish or orangey. It should be free of inclusions to the eye, although inclusions under magnification are common. It is very rare in sizes over 2 1/2 carats. Ruby is the birthstone for July.


Sapphire: Fine quality sapphires are neither too dark nor too light. The best colors are medium-dark, true blues. without any greenish or purplish tones. They should be free of any weak color areas or banding of color-called zoning. An inky-dark blue is never wanted in sapphire. Color for sapphire is not limited to blue; in fact sapphire comes in a rainbow of colors from pink to green to yellow and more. These are referred to as "Fancy" sapphires. The September birthstone is sapphire.


Emerald: Medium dark to dark, clear green is the hallmark of a fine emerald. There can be a faint hint of blue or yellow in the green and still be beautiful. Very light emeralds have a small fraction of the value of their more intense counterparts. Emerald is generally included by its nature. So a clear gem commands a higher price. Emerald is the birthstone for May.


Other fine gems range from well known topaz, aquamarine and amethyst to the lesser known spinel and tourmaline. Familiar gemstones such as garnet have some surprises too. Most people think of garnet as simply red but garnet comes in a paint-box of colors from raspberry to orange to green and more. Some are very rare like green Tsavorite garnet and demantoid; others are readily available like pyrope and almandite reds.


Let Jessop's gemologists introduce the beauty of gemstones to you. Our carefully chosen collection of the world's most beautiful gems features both loose and mounted gemstones. Shop our San Diego store for gorgeous colored gemstone jewelry. Jessop's San Diego location is the place to find that special loose gemstone, just waiting to be set in a custom design.


Traditional Birthstones

The possible origin of the birthstone may come from a biblical reference to 'Aaron's breastplate' which was said to contain twelve gemstones; the specific gems are not known. Early people held many beliefs about the powers or curative effects of gems. The Victorians liked sentimental gifts and tokens; having a special birthstone was a popular idea.


The modern list was created in 1912. Citrine is a somewhat new addition to November and Tanzanite is a very new December addition, added in 2005. For the birthstone wearer there are no hard and fast requirements other than a love for gemstones.

January - Garnet February - Amethyst
March - Aquamarine or Bloodstone
April - Diamond
May - Emerald
June -Pearl, Moonstone or Alexandrite
July - Ruby
August - Peridot or Sardonyx
September -Sapphire
October - Opal or Tourmaline
November - Topaz or Citrine
December - Tanzanite or Turquoise

A brief word about gemstone enhancements

Rare and beautiful gemstones owe their gorgeous looks to nature. But sometimes natural beauty can be improved and gems may get a little help to improve their appearance. The many types of gem treatments are generally called enhancements.


Many colored gemstones in the global marketplace today are enhanced. Usually this is done as an industry-wide and acceptable practice. Sometimes it is done to defraud a customer. Gemstones are often enhanced to supply market demands or create desirable colors. For example blue topaz is created from colorless, or brownish, topaz using heat combined with irradiation treatment to turn it blue. Wouldn't exist otherwise. Tanzanite is another gem heated to create the lovely blue-violet color we admire.


Sometimes a fragile gem is made more stable through enhancement. Emerald is a gem which has been oiled for centuries to soften the look of its natural and common inclusions. Today's technology has created an enhancement for emeralds that masks the natural inclusions and also makes the gems more stable for wear. Most all emeralds in the marketplace today are enhanced in some way. Sapphires are routinely heated to improve the color and appearance, as are rubies.


Not all enhancements are created equal. While oiling an emerald with colorless oil is benign, adding an epoxy resin tinted green is an enhancement that will improve the looks but in reality the gem is no better. Sometimes the changes are not permanent. Naturally colored black or golden Tahitian pearls are rare and beautiful. Sadly, many pearls have been dyed to create shades of black and gold. Even diamonds may be altered to improve a flawed appearance. When gems are dyed, or significantly treated, a customer should be informed...if not it is an ethical and trade violation.


Many deceptive enhancements are not disclosed creating the illusion that a gem offers beauty at a bargain. This happens to shoppers abroad and to buyers here, too. A savvy shopper needs to ask questions. Jessop's focus is on unenhanced, natural gems, and gems which have only industry acceptable minor enhancements for fine gemstones. We support a policy of full disclosure. Jessop's certified gemologists can answer your gemstone queries.


This is a brief overview of some enhancements. For more information visit


Synthetic or laboratory created stones, are not made in nature but are grown by laboratories. The early days of man-made stones produced sapphires and rubies as far back as the early 1900's. We see these in estate jewelry occasionally. Many types of synthetic stones are mass manufactured today and the consumer must be informed. Some creations like cubic zirconium, CZ, do not even have a counterpart in nature. Jessop's does not carry synthetic stones.
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