New This Month


Martha Stewart Living, November 2000

The rational person accepts that sapphire, September's birthstone, is an aluminum oxide crystal colored by traces of iron, titanium, vanadium, or chrome. But peering into the gem, you can just as well imagine, as did the ancient Persians, that it is a chip off the precious pedestal on which the Earth balances, whose dancing reflections create the multifarious colors of the sky.

For the Persians as well as for the Greeks, Romans, Egyptians, Incas, and Aztecs, the twelve gemstones now attached to the calendar year for sentimental reasons were items of great power: amulets, guardians, even convoys into the afterlife. Cleopatra ground pearls into her wine to drink in their beauty. Emperor Nero watched the gladiators through sunglasses made of emeralds. In medieval Europe, aquamarines in the mouth allowed safe questioning of the devil; wearing topaz protected against sudden death. The custom of giving and receiving these stones is a poignant vestige of humanity's efforts to comprehend the mysteries of the universe and to summon its aid to safeguard loved ones.

The association of specific gems with the months of the year has a long history as well. Among the earliest known links to the twelve birthstones commonly accepted in the United States was the holy breastplate of Aaron,brother of Moses, who helped lead the Israelites from Egypt; the gems affixed to the breastplate, representing the twelve tribes of Israel, are listed in chapters 28 and 39 of Exodus in the Old Testament.Wearing birthstone jewelry is a custom that began in Poland in the 1700s. By the twentieth century, various lists of birthstones, all apparently evolved from Aaron's sacred garment, had found sponsors in jewelry and gemstone trade associations. The wreath of gems represents the calendar of birthstones adopted in the United States by the National Association of Jewelers in 1912.

The peculiar magic attributed to specific birthstones is a matter of personal opinion, but all the gems share a true and transcendent power: They command your gaze. They escort you into the depths and facets of their crystalline and ordered universe. They gather light and shine it back on you. They link you inextricably to someone you love (or, in some cases, once loved), and to other times in your life. They keep your history.

The power of gems to take you in can actually be explained. It is simply a matter of how jewels play with the electromagnetic vibrations we call light. The come hither properties of precious stones -- color, fire, luster, and luminescence -- are optical. Seeing is succumbing.

Light travels in waves; the human eye perceives these waves as colors. If all wavelengths of light are absorbed by a gemstone, it appears colorless. The inherent color of a gem, as defined by gemologists, is the characteristic color it presents in the absence of impurities.But in many cases it is those very impurities, just like our own signature imperfections, that give the stones their color and, in turn, their personalities. Serendipitous trace minerals present in gems -- especially chrome, iron, cobalt, titanium,manganese, nickel, and vanadium -- absorb different wavelengths of light and thereby give each stone its own particular color. That is why so many gems -- not just diamonds and sapphires but also garnets, topazes, and tourmalines -- come in so many dazzling hues.

The cut of a gem also affects its color, by altering the way light travels through the jewel. Most cuts fall into or between two categories: the brilliant,which has triangular or kit-shape facets; and the step, whose rectangular facets descend in parallel planes. A full-cut brilliant must have at least 58 facets, allowing a stone the most spectacular light show possible. Elegant step cuts are often reserved for gems whose color and transparency are magnificent in themselves. A third category, the cabochon, or dome-shape cut, can show off the polish of a stone and bring out features known as "inclusions": internal solids, liquids, and gases that create effects such as a sapphire's six-pointed star.

Gemologists classify birthstones, like all gems, according to their constituent minerals. Diamonds, for instance, are composed of carbon atoms that crystallize instantaneously under extreme pressure and temperature deep in the planet's core. The corundum group, which includes ruby and sapphire, are crystals of aluminum oxide. Emeralds and aquamarines are members of the beryl family, whose signature elements are aluminum, beryllium, silicon, and oxygen. These mineral classifications are a reminder of the humble origins of gems and their formidable transformation from rough to cut stone. A gem is quite literally the cut and polished offspring of a piece of Earth that has been shaped by time and powerful physical forces. Gems-to-be are spewed from volcanoes and tossed up by ocean waves. Or they rest quietly in sedimentary, igneous, and metamorphic rock,waiting to be unleashed by water, wind, or the pickax of a miner. Prospecting for diamonds is often a methodical process backed by enormous capital, but many deposits of other gemstones, even today, are discovered by accident, which only adds to their allure.

Every birthstone contains the story of its parent rock, its birth, its passage from gem cutter to merchant, its accumulated lore and its provenance. It is like a book that will never conclude, for a new chapter begins each time a gem is given and received as a token of love.

Birthstone Glossary

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