What you should know about Colored Gemstones
Beauty. Rarity. Durability. These attributes attract us to colored gemstones for personal adornment and make gemstones valuable and precious. Colored gemstones provide the opportunity for unique personal expression.
Characteristics of Colored Gemstones
Beauty – Most colored gemstones derive their beauty from their color – purples, blues, greens, yellows, oranges, reds. In certain colored gemstones color occurs naturally. Satisfying hues are intrinsic in some garnets, for example. The natural beauty of many other colored gemstones is enhanced by man. For nearly as long as people have worn rubies, for example, we have known how to treat a rough ruby with heat to obtain a desirable red color. Not all rubies are heat treated, but a vast majority are.
Gem cutters work to achieve a pleasing and affordable mix of color, weight (measured in carats), and a safe shape for mounting. During creation a gemstone’s size is constrained by nature. For example, while large and beautiful amethysts are readily available, an alexandrite of large size is extremely rare.
Sparkle adds to the beauty of a well-cut colored gemstone. The cut of a colored gemstone describes its shape and how it is fashioned. Some gemstones, such as opal, are suited to a smooth, rounded surface. Others, such as sapphire, are more frequently shaped with a precise series of flat, symmetrical planes, called facets, which make the most pleasing illumination of the gem’s color. Some cutters today may also use convex or concave facets, shaping colored gemstones like small sculptures.
The clarity of colored gemstones contributes to their beauty. Unless a gemstone is opaque and blocks all light, how light moves through the gemstone affects its beauty. Some gemstones have a few internal inclusions to interrupt the passage of light, as is the case with most pieces of tanzanite. Others have characteristic inclusions. For example, some emerald has a “jardine” (garden), which makes each gem truly unique.
Rarity – Across time and cultures, people have adorned themselves with rare gem materials. From pearls and corals plucked from the seas, to bright colored pebbles found in the soils settling at the mouths of rivers; from the collection of gemstones mounted in the breastplate of Aaron as accounted in ancient scripture, to the historic gemstones mounted in the crown jewels of European monarchs, we let ourselves be known through the gemstones we choose to wear. These gemstones are precious because they are rare.
Because of their rarity, gemstones in which color is naturally occurring are generally more valuable. Many gemstones are treated or enhanced in some way, such as with heat or safe irradiation, to achieve the beautiful color or clarity we desire in the sizes we desire. These gems, which are less rare, can also be very valuable. Synthetic colored gemstones have all the optical, physical, and chemical properties of naturally occurring gemstones, but they are created in a laboratory rather than occurring in nature. For some budgets, these synthetic materials are an acceptable choice.
Durability – A gemstone’s ability to be fashioned, mounted, and worn is a function of how durable it is – a matter of both hardness and toughness. Some gemstones, such s sapphire, ruby and garnet, are well-suited to an active daily life and work in rings, bracelets or cufflinks. Others such as emeralds, pearls and opals, call for earring or necklace mountings to keep them beautifully displayed but out of harms way.
Gemstone Value Factors
For the most part gemstone varieties, color has the strongest impact on gemstone value and price. Follow these general guidelines for evaluating color:
Judge each gemstone variety by its own set of characteristics. The most valuable colors are usually pure and vivid with a medium to medium-dark tone. Value decreases as the color moves toward a very light or very dark shade and shifts from pure hue to mixed colors. Due to the rarity, fine gemstones with no enhancements are generally more valuable.
Regardless of a gemstone’s rarity or inherent value, only you can determine the colors you find most attractive. When a gemstone comes in a wide color range, which one is best? That’s easy – the one you like the most! With something as subjective as color, it is impossible to equate rarity and price with beauty and value. Trust your eye to pick out the colored gemstone that is right for you.
A gemstone’s clarity is determined by the unique environment in which it forms. For example, the formation process of aquamarine usually results in a transparent and inclusion-free gemstone when viewed by the unaided eye. On the other hand, emerald forms in an environment that almost always produces some visible inclusions. This means that finding an inclusion-free emerald would be highly unlikely, but for aquamarine it is relatively common.
Think of inclusions as a gemstone’s birthmarks, not flaws; they add individuality to make your gemstone one of a kind. We can help you understand how each gemstone’s clarity relates to its value.
The way a gemstone is cut can have a tremendous impact on the gem’s beauty. A well-cut gemstone should show large areas of brilliance and color when facing up. Light and color should reflect evenly from inside the entire gemstone as you slowly rock back and forth.
Large dark areas that look washed out or that you can see straight through indicate a gemstone that was not cut with maximum beauty in mind.
The “carat” is the standard unit of measurement for the majority of gemstones. As a general rule, a gem’s per-carat price will increase as its size increases. The rarer the gemstone, the larger the price increase. For example, rubies rarely occur in sizes over a carat; therefore, a very fine four-carat ruby might sell for four or five times the price per-carat on a one-carat ruby.
Synthetic Gems & Enhancements
To achieve beautiful colors or improved clarity, many gemstones – including popular gems like ruby, sapphire, citrine, and tanzanite – are treated or enhanced. Some enhancements create special care and cleaning considerations that we can share with you. Some of the most common and beneficial treatments include:
Heat – Used for centuries to improve the color and/or transparency of some gems. Popular colored gemstones routinely enhanced with heat include amber, amethyst, aquamarine, carnelian, citrine, morganite, tanzanite, topaz (pink) tourmaline (blue and green), and zircon.
Irradiation – Irradiated gems on the market today are completely safe. Popular colored gemstones routinely enhanced with irradiation include diamond, cultured pearl, topaz (blue – combines heat and irradiation) and tourmaline (pink, red).
Bleaching/Dying – These treatments are most often used on softer and non transparent gems. Popular colored gemstones routinely enhanced by bleaching or dying include black onyx (and other types of chalcedony), cultured pearl, jade, lapis, and turquoise.
Filling – Surface-reaching cavities or fissures are filled with colorless glass or similar substances to improve a gemstone’s appearance. Popular colored gemstones routinely enhanced by filling include diamond, emerald, and ruby.
Buying Colored Gemstone Jewelry
When buying colored gemstone jewelry, select what you consider beautiful. Because of the subtle differences in the tone and hue of the colored gemstone you are considering, look at several to find the one you prefer. We offer loose colored gemstones as well and are able to help you create a personalized mounting of your choice. You may prefer to buy a finished jewelry item instead and we can help you with that as well. Let us know how you see yourself wearing the piece so that we can help you select a mounting consistent with your lifestyle. This will provide the best safeguard for your purchase.
Information courtesy of Jewelers of America.