If you are shopping for a large diamond, .75 carat or more, you should look for a loose stone, or ask the stone be removed from the mounting if possible. When it is loose ask to see the stone weighed. Have the seller show you its color grade and show…
Rubies and sapphires are the same mineral: corundum, with different trace minerals creating a wide variety of color. Rubies and sapphires have been treasured for thousands of years. They were named long before anyone realized they were the…
Ironically, chrysoberyl varieties include two of the world’s most exotic and expensive gems, alexandrite and cat’s-eye chrysoberyl, while yellow or yellowish-green faceted chrysoberyl is a nondescript variety in the low to moderate…
Aquamarine was the talisman of the sailor for centuries, its colors resemble those of the sea and it has a delicate watery appearance that perfectly suits its name. It is the blue-green to green-blue variety of beryl. It ranges from an icy pale…
To simplify your pursuit of gemstone knowledge, the varieties discussed in this book will be described in the mineral species. The reason for doing it this way is that each variety of a particular mineral shares common physical and optical…
The treatment and enhancement of gemstones has existed for centuries. Some enhancements improve on nature slightly, are undetectable, and they are permanent; this provides the gem market with a larger supply of beautiful gemstones. Other…
The valuation of a gemstone is derived from the “FOUR C’s”: carat, color, clarity, and cut. Understanding all four of these is vital background to the buyer. If you are buying an expensive stone with a price in four figures or more, buy it loose…
The most valuable gems come from crystallized minerals that have formed under heat and pressure deep inside the earth. The perfect order of the crystal structure is what makes gemstones transparent yet durable. Crystallization of minerals…
The beauty, color, and brilliance of each different gemstone variety is a result of its unique set of physical and optical properties. Gemologists study these properties to identify gemstones and to read where they are from and how they were…
Gemstones have been treasured by humankind since the beginnings of civilization. Every ancient civilization found practical and decorative purposes for gem materials. The durability of gemstones lent itself to practical uses: ancient…
You may never have heard of iolite. It isn’t a household word, but it is an attractive indigo colored gemstone. It has been called a “water sapphire”. Iolite is highly trichroic; in one direction it is totally colorless, this aspect was the origin…
Andalusite is an unusual stone. It shows flashes of several different earth tones in the same stone. Because of its combination of colors, it has been called “poor man’s alexandrite,” but it does not look like alexandrite at all. Andalusite…
Each gemstone species has unique properties; the informed buyer can save time when he knows what is feasible and what is not. Specific prices will not be listed in this book for two reasons: price lists can be very misleading if you do not truly…
This book is written as a guideline for the potential buyer of gemstones that are mined from the earth or formed by some natural organic process. As a knowledgeable buyer you will be a confident one. Natural gemstones offer the consumer many…
At the time of Moses twelve gemstones comprised the Jewish High-Priest’s Breastplate of Aaron; each stone represented one of the twelve tribes of Israel. In ancient India, gems were associated with planets and astrological signs. From these…
here are many minerals accepted as gem materials. Some gem materials are organic in origin rather than mineral, such as amber and coral. Here are some additional gems of interest you may encounter on your gem quest.
If you are looking at a tanzanite it is critical to view it under different lighting conditions. In daylight tanzanite will display the most blue, incandescent light will bring out the violet color. Generally those stones that are brilliant…
The first man-made gem materials dates back a few thousand years; early Romans made glass beads and gems. Since natural materials are also in short supply and often hard to mine, man will look for alternatives. Glass gem substitutes are still…
Zircons were called “jacinth” or “hyacinth” in older writings. Zircons are exceptionally brilliant gemstones; the high zircon has the highest refractive index of any natural transparent gemstone. High zircons are usually blue or colorless.…
The most common tourmaline colors are greens and pinks. Yellow and violet tourmalines are relatively rare. Tourmaline that falls into the distinctive red colors is called rubellite. Blue colors are called indicolite. Chrome tourmaline…
Quartz is generally divided into two groups: the transparent crystalline varieties and the translucent to opaque chalcedonies that are microcrystalline forms of quartz. There are many different varieties in these two types but they have…
Pearls are organic gem materials form in a variety of mollusks when the mollusk covers an irritant with layers of nacre. Oysters, mussels, conch, and abalone can produce pearls. Oysters and mussels can do this job by themselves when an irritant…
Every opal is unique in appearance. Opals contain fireworks of every possible color dancing inside them. The flashes of color that make opal such an interesting stone are referred to as play of color. Opals will vary in body color, which is the…
Jade is a confusing term since it is used to refer to two different gem materials. The two jades, jadeite and nephrite, can be somewhat similar in appearance, so the confusion persists. Jadeite was first imported into China in 1784 from Burma.…
Garnets are a group of related minerals which have slight variations in chemistry but a common cubic crystal structure. Many garnets fall in between some varieties and defy assignment to a specific group. When in doubt just call it a garnet.…
Turquoise has a long history as a gemstone. It was one of the favorites of the ancient Egyptians. Its name was derived from the word “Turkish”, which referred to the ancient source of turquoise in present day Iran. Turquoise will vary in color…
Topaz is a gem that is very often eye clean, so stones with good clarity are available. The red color can be a strawberry hue: these are quite hard to find and will command the highest price. Deep pinks can be exceptionally beautiful. Pink topaz…
The most famous ruby in the world is actually a spinel! It is the “Prince Edward Ruby” which is the center of attention on British Crown of State: this crudely shaped cabochon weighs about 167 carats. It is a magnificent red color. Spinels and…
Cleopatra was reported to have a fine collection of emerald jewelry, but rumor has it that it was really peridot. We hope she won’t be too disappointed. Peridot was mined on an island in the Red Sea called Zebirget or St. John’s Island, thousands…
Lapis lazuli differs from other gem materials because it is a “rock” composed of several minerals rather than being a single mineral as the other gemstones are. The components of lapis lazuli include sodalite minerals, calcite, and pyrite.…
The feldspars are a group of related minerals which, as a group are the most abundant minerals in the earth’s crust. However, only a tiny percentage of the feldspars fall in the “gem quality” range. The members of the feldspar group have similar…