Cut: Refers to the geometric shape and proportions of a gemstone. A gemstone’s cut is what most directly affects its sparkle or brilliance.

Facet: A flat cut on the surface of a gemstone.

Fire: Flashes of rainbow colors. Also called “dispersion.”

Hardness: Resistance to scratching. The higher the number, the more resistant.

Hue: Another word for color.

Luster: The shininess of a jewel.

Opaque: The opposite of transparent. Light cannot pass through an opaque gemstone, therefore they do not have any sparkle or fire.

Saturation: This term refers to how pure or deep a gemstone’s color is. Some gemstones, like aquamarine, have a naturally low saturation (very light blue) while other gemstones, like amethysts, can have very high saturation (rich, dark purple).

Sparkle: The white light leaving a jewel, traveling upward, which is visible to the eye. Sparkle is often referred to as “brilliance.”

Toughness: Resistance to breakage.

Gemstone Shapes & Cuts
These are the common shapes or cuts for gemstones, each lending a different look and allure.

Baguette: Baguette means “stick” or “rod” in French, which makes it a very appropriate name for this gemstone shape. Diamond baguettes are often used as accent stones to flank a primary stone.

Brilliant: Any gemstone cut with 58 facets, which produces the maximum possible sparkle. A brilliant cut can have several shapes, including round, oval, pear, radiant and heart.

Cabochon: This shape features a rounded, perfectly smooth surface instead of facets. It is the oldest gemstone shape and is commonly used with opaque stones such as opal, jade and turquoise.

Cushion: A very popular style for most of the 19th century, cushion shapes are slightly domed with rounded corners that make the stone look like a pillow. In fact, this shape is often referred to as a “pillow cut.” It looks particularly beautiful in candlelight.

Emerald: With its long, steep facets, emerald cuts tend to flash rather than sparkle.

Fancy: Technically, this term refers to any type of gemstone that isn’t round, but many jewelers reserve it to describe the more exotic gemstone shapes such as marquise, heart, pear and trillion.

Heart: Often described as a custom cut, heart-shaped gemstones are very popular for pendants.

Marquise: According to legend, this shape was commissioned by King Louis XV to resemble the smile of his mistress, Marquise de Pompadour. Ideal marquise cuts have a length to width ratio of 2:1.

Oval: Similar to the round shape, oval gemstones produce a high amount of sparkle and fire.

Pear: This is a classic teardrop shape that is ideal for earrings and pendants.

Princess: This a relatively new shape that combines the sharp, flat edges of an emerald shape with numerous small facets, which produce both sparkle and fire.

Radiant: This shape is similar to emerald, but it adds extra facets on the edges and corners to increase the gemstone’s sparkle.

Round: This classic shape produces maximum sparkle and fire, making it an ideal shape for diamonds.

Tapered Baguette: A tapered baguette is a baguette shape with one end that is narrower than the other.

Trillion: A very striking, usually three-sided shape, trillion gemstones (especially diamonds) are celebrated for the intense fire they produce.

The Mohs Scale
The most common measure of a gemstone's degree of hardness is based on the Mohs Scale. Devised by German geologist Friedrich Mohs in 1812, the Mohs Scale grades minerals on a comparative scale from 1 (very soft) to 10 (very hard).

Hardness is generally associated with durability and the ability to resist breakage. When referring to gemstones, however, hardness more accurately means the stone's ability to resist abrasion. What the scale means is that a mineral of a given hardness rating will scratch other minerals of the same rating, as well as any minerals of a lower hardness rating. For example, rubies and sapphires, which are composed of the mineral corundum and have a Mohs rating of 9, will scratch each other, as well as topaz (rating 8) and quartz (rating 7). But they will not scratch diamonds, which are rated 10 and considered the hardest substance.

The numeric values assigned to each interval of hardness are not equal. Some stones are disproportionately harder than others. Because Mohs Scale wasn't made for exact precision, it uses half numbers for in-between hardness ratings.

Pearl:

Often referred to as a gift from the sea, pearl’s origin has been an object of folklore throughout history. Early Chinese myths told of pearls falling from the sky when dragons fought. Ancient Persian legend said that pearls were tears of the gods. In classical times, it was believed that pearls were formed when moonbeams lit upon shellfish, while Indian mythology suggested pearls were formed when dewdrops fell from the heavens into the sea.

In truth, pearls are lustrous gems with an organic origin. They are formed inside mollusks such as oysters, clams and mussels when an irritant such as a tiny stone, grain of sand or small parasite enters the mollusk's shell. To protect its soft inner body, the mollusk secretes a smooth, lustrous substance called nacre around the foreign object. Layer upon layer of nacre coats the irritant and hardens, ultimately forming a pearl.

This process of building a solid pearl can take up to seven or eight years. Generally, the thicker the nacre becomes, the richer the “glow” of the pearl and greater its value. While pearls that have formed on the inside of the shell (called blister pearls) are usually irregular in shape and have little commercial value, those that are formed within the tissue of the mollusk are either spherical or pear-shaped and are highly sought-after for jewelry. Most pearls on the market measure 7.0-7.5mm in diameter, but can be found as small as 1mm or as large as 20mm.

Although some pearls are found naturally in mollusks (considered the most valuable), the vast majority of pearls are grown, or cultured, on pearl farms. To instigate this culturing process, a small shell bead, or nucleus, is surgically inserted into the mantle of an oyster. Despite the fact that pearls are harvested in great quantities on pearl farms, producing a quality pearl is an extremely rare event. It is estimated that half of all nucleated oysters do not survive and, from those that do, only 20 percent create marketable pearls.

Cultured and natural pearls can be distinguished from imitation pearls by rubbing them gently against the edge of a tooth. Cultured and natural pearls will feel slightly rough, like fine sandpaper, because of the texture of natural nacre. Imitations will feel quite smooth because their surfaces are merely molded or painted on smooth beads. Since nacre is organic, pearls are quite “soft” and rank only a 2.5-4.5 on the Mohs Scale. The gems are very sensitive and special care should be taken when wearing and storing them.

The value of a pearl is judged by several factors, and high-quality pearl strands should feature pearls well-matched in these factors: “orient,” the lustrous iridescence that’s produced when light is reflected from the nacre, should glow with a soft brilliance; the nacre’s texture should be clean and smooth, absent of spots, bumps or cracks; the shape of a pearl should be symmetrical and generally the rounder a pearl is, the higher its value; and although pearls come in many different colors (depending on the environment and species of mollusk), the most favored are those that have a rose-tinted hue.

Pearls are cultured in a variety of sizes, shapes and colors. Akoya pearls are the classic round pearls found in most pearl jewelry. They are mainly grown in the waters off Japan and are found in a range of hues, including white, cream, pink and peach. Mabe pearls are grown in Japan, Indonesia, French Polynesia and Australia. They are usually flat-backed and often called blister pearls because they form against the inside shells of oysters rather than within oysters’ bodies. Tahitian pearls are grown in French Polynesia and come in a range of colors, including gray and black with green, purple or rose overtones. Because of their large size and unique dark colors, they command very high prices. Also prized for their large size, white South Sea pearls are grown in Australia, Indonesia, the Philippines and other areas of the South Pacific.

Freshwater pearls come in various colors and are grown in bays, lakes and rivers primarily in Japan, China, Europe and the United States (Mississippi River). They are often irregularly shaped and less lustrous than saltwater cultured pearls, making them substantially less expensive.

Pearls have been treasured throughout ancient folklore and history. Aphrodite, the Greek goddess of love, considered pearls to be sacred. The Greeks prized the gems for their beauty and believed that wearing pearls would promote marital bliss and prevent newlywed women from crying. In ancient Rome, pearls were considered the ultimate symbol of wealth and status. The ancient Egyptians were buried with them and the Egyptian queen Cleopatra favored pearls immensely. It is said that while dining with Mark Anthony, she purposely dropped a pearl into her drink to demonstrate the wealth of her rule.

As early as 2000 B.C., pearls have been used as medicine in China, where it was believed to represent wealth, power and longevity. Even today, low-grade pearls are ground for use as medicine in the Orient. Arabs and Persians also believed it was a cure for various kinds of diseases, as well as insanity.

Long ago, when pearls were not cultured and thousands of oysters had to be searched for only one pearl, the gems were important financial assets, comparable in price to real estate. Some European countries even banned all but nobility from the right to wear them. Medieval knights wore them in battle as a talisman against injury, while warriors in India encrusted pearls into their sword handles to symbolize the tears that swords can bring.

Today, the pearl is a universal symbol of innocence and purity. It is the birthstone for June and is considered the traditional gift for couples celebrating their 3rd and 30th wedding anniversaries. Many believe the gem gives wisdom through experience, quickens the laws of karma and cements engagements and love relationships. It is also considered to offer the powers of wealth, protection and luck.

The largest pearl in the world is approximately 3” long and 2” wide, weighing one-third of a pound. Called the Pearl of Asia, it was a gift from India’s Shah Jahan to his favorite wife, for whom he also built the Taj Mahal. Another famous pearl is called “La Peregrina,” or “the Wanderer,” and is considered by experts to be the most beautiful pearl in the world. Pear-shaped and measuring 1-1/2” in length, it is said that 400 years ago the pearl was found by a slave in Panama, who gave it up in return for his freedom. In 1570, the conquistadors sent the pearl to King Philip II of Spain. The pearl was passed to Mary I of England, who gave it to Prince Louis Napoleon of France, who sold it to the British Marquis of Abercon. After disappearing for a century, the pearl turned up once again in 1969 at a New York auction house. It was purchased by actor Richard Burton for his wife, Elizabeth Taylor.