Monday, December 21, 2009

Diamonds: How are They Valued?

Cut: A diamonds' cut influences the brilliance, or light reflecting qualities of the gem, at the same time it enhances the fire of the diamond, or that rainbow quality. A good cut enhances both qualities, fire and brilliance, without sacrificing one for the other. A well cut diamond balances the depth of the diamond to the breadth of the diamond. A poorly cut diamond of the same size can look flat and be more vulnerable to cleavage and breakage.

Clarity: Diamonds are crystalline carbon. The clarity of the diamond refers to the purity of the stone and imperfections within the crystalline structure and on its surface. There is no such thing as a flawless diamond in nature. Sometimes this clarity factor is referred to as the cleanliness of the stone. If a stone is viewed under 10x magnification and no imperfections can be seen, either internally (inclusions) or externally (blemishes), the stone is referred to in the trade as flawless. A microscopic speck of carbon, undetectable by the human eye, can bring down the value of the diamond substantially. There are five commonly used methods for grading clarity. Just keep in mind the cleaner the stone, the more valuable it is, the more it costs.

Wednesday, October 7, 2009

Fancies? Yes. Diamonds come in colors.

Think of diamonds and you think of breathtakingly clear stones, clear as water, pure as ice. But diamonds do come in colors. Diamonds are normally graded from colorless or rare white, to brown. Colors deeper than light yellow are not usually used in jewelry making, although on occasion, champagne diamonds or cognac diamonds appear. These are really, in most cases, white diamonds of an inferior color grade, rather than fancy diamonds.

The colorless is the most expensive of the white diamonds. Diamonds with a faint tint of yellow are less valuable and a yellow color visible to the naked eye are the least valuable.

Fancies are the term used for colored diamonds. Diamonds can be found in every color and intensity: red, blue, yellow, green, and lavender. The intensity of the colors can range from palest pink to red, lightest blue to sky blue and so forth. Fancy diamonds are rarer than white diamonds. The most common fancy colors are yellow ranging from canary yellow, orange, and brown. Colors such as pink, lavender and light green occur much more rarely than the yellow colors. Most valuable of all are the deep reds, greens and blues.

One word of caution: colored diamonds can be created artificially by subjecting inexpensive yellowish and brown stones to radiation or heating. Fancy diamonds, other than green, can be tested to see if the color is natural or the color has been induced.

The Hope diamond is an example of a fancy blue diamond. The Argyle Mine in Australia produces a small number of red diamonds and is the world's largest producer of pink diamonds. Several of their pink diamonds have sold for over $1,000,000 per carat.
The Dresden diamond is an apple green diamond weighing 40.70 carats. The Tiffany diamond is orange.

At certain times of the day the sky is colored. At sunrise you have what colors? Yellow, orange, and red. Suppose your diamonds take shape at these moments. They are reflecting the yellow or the red, and it becomes a part of them. Or if it is not sunrise or sunset, but the middle part of the day when the sky is blue, they reflect the blue. Just at the moment they turn hard they take on the color of the sky. If they are formed at night when there is no color for them they become pure and colorless, what we call white.

Monday, September 14, 2009

Sapphires, Rubies, and Emeralds: How Colored Gemstones Are Valued

The colors of the rainbow caught forever in glittering jewels that take your breath away. Colored gemstones can rival diamonds for their beauty but how are they valued?

Even though sapphires, rubies and emeralds differ in color and weight for example, there is a consistency in how they are valued. And that includes lesser known gemstones like tourmaline, alexandrite, peridots, and garnets as well. The four characteristics that determine value in a colored gemstones are color, clarity, cut, and carats, but the most important is color, color, and more color.

The intensity of the color and the closer it comes to the true spectral color means the stone has more value. Emeralds should be a pure green, rubies the reddest red, and sapphires a deep rich blue. As the color varies from the spectral ideal, the value declines. For example: Burmese rubies have the best color. Rubies that are a lighter red, reddish orange, or with a touch of brown or a bit of blue aren't nearly as valuable.

Color is measured in intensity or saturation, in other words the vividness of the color. It also reflects the hue, or how close the color approximates the pure spectral color; tone which is how light or dark ie., how much black or white is in the color; and finally the distribution of the color or how even the color is across and within the stone.

The other factors of clarity, cut, and carats are not as important to the value of a stone that has the best color and inversely have a greater impact on the value of a stone that is not as pure a color.

Clarity is the absence of internal flaws that can be seen with a magnification of 10. Most colored gemstones naturally have inclusions or flaws. A prime example are emeralds which very rarely don't have flaws. The lighter the color of the stone the more visible the flaws become, while the darker the color of the stone the less obvious. The type of flaw and where it occurs in the stone affects its value as well.

Cut is the way a stone is faceted to bring out the best characteristics of that particular stone for its type. The cut brings out the color, fire, and brilliance of the stone, not sacrificing one for the other. Unlike diamonds colored gemstones can also be presented as a smooth rounded surface known as cabochon cut. Cabochon cut sapphires and rubies often reflect a star and are known as star sapphires and star rubies.

Carat is the weight of the stone, not how big it is. Different types of gemstones have different weights when cut to the same size. The density of rubies is greater than the density of emeralds so a one carat ruby will be smaller than a one carat identically cut emerald. Stones can be cut to look bigger as well. Some gemstones are more readily available in larger weights such as amethysts or tourmalines, that say emeralds. For example: An 18 carat tourmaline will have a lesser value per carat than a 5 carat alexandrite because large tourmaline stones are more common than large alexandrite stones.

The best safety precaution when buying gemstones or gemstone jewelry is to buy from a reputable jeweler. You will get what you pay for. Peace sign jewelry from heavenly Treasures does just that

Monday, June 29, 2009

Pearls before Swine

Pearls, beautiful, lustrous, glowing pearls. And to think it all started with a grain of sand.

The mollusk, that' s oyster to you and me, opens its shell to pass fresh water over itself and snag tiny bits of food. Sometimes what it snags is a grain of sand or piece of shell. If the mollusk can't get rid of the bit of grit it begins to coat it with a substance it produces called nacre. Coating the grain of sand makes it less irritating. As time passes the grain is coated with many layers of nacre. Eventually you end up with a lustrous pearl.

Not all pearls are gem quality. The pearl can be lopsided, have an irregular surface, or the coloring of the pearl is grayish instead of glistening. If the irregularity is only on one side and the pearl looks good otherwise it can be set in jewelery with the flaw at the back of the piece where it won't be noticed.

Pearls can be from fresh water or salt water mollusks. Salt water is more expensive.

Colors range from white, yellow, pink, to gray. South Sea Pearls, sometimes called Tahitian pearls, are some of the most expensive pearls. They are larger, because the mollusk is larger, and the colors are iridescent black, purple, and dark gray. The pearl looks like a rainbow is playing against the dark surface.

Natural pearls are very expensive and difficult to find in jewelry since the Japanese began culturing pearls. Cultured pearls are simply oysters in an oyster bed that has been seeded with a nucleus.

Good cultered pearls have been left in the oyster over several years to build up layers of the pearl. Cheap cultured pearls start with a much bigger seed core and then left in the oyster only long enough to gather a few layers. Those layers can wear off.

The value of a pearl is based on 5 factors: cleanliness, shape, luster and orient, and color.

Friday, May 29, 2009

No matter how you cut a diamond

Cutting a diamond can only be done with another diamond. The practice is painstaking, one wrong move and the diamond can cleave into pieces destroying its value. A diamond can be cut so that its face is broader and the depth shallower. That makes the diamond "spread" or look bigger than it actually is. Diamonds are cut to increase their brilliance or sparkle and their fire or that rainbow quality. Some cuts favor one characteristic over the other, but in well cut diamond both should be enhanced.

The cut of the diamond refers to the precision and expertise of the finished shaped stone. A good cut can enhance a mediocre quality diamond and a bad cut can literally destroy the value of a good stone. Diamonds are cut in facets, or flat planes. Each should be precisely in alignment. Modern diamonds are always faceted to play up their inherent qualities. Other gems can be rounded like a star sapphire, that particular shape is known as cabochon.

The facets reflect light back through the diamond and causes the glitter and rainbow effect so characteristic of diamonds. Beautifully cut diamonds display the most vivid fire with the least loss of brilliance.

The classic round cut has 58 facets. It allows the most light to be reflected back up through the diamond. The face of the diamond is the flat surface you see when looking directly down at a diamond. It is surrounded by 33 facets. The girdle is the rim around the crown of the diamond. The pavilion is the bottom portion of the diamond and has 24 facets plus the tiny facet at the point of the pavilion called a cutlet.

The crown portion of the diamond should measure 1/3 of the depth of the pavilion. Diamonds are always faceted to play up their inherent qualities. Choosing the right cut can enhance a diamond's color (yes diamonds do come in colors) and hide flaws. A poorly cut diamond can be more prone to shearing or shattering.

Diamonds can be cut to look larger by decreasing the pavilion and increasing the crown. In other words the diamond is broad but shallow.

Small diamonds can be cut with only 17 facets and are known as single cuts. Swiss cut can be used for small diamonds as well and have only 33 facets.

There are other cuts for diamonds. The quadrillion is a square cut known as the princess cut. A round diamond can be cut with 144 facets. And a marquise shaped diamond, (think of a football with pointed ends) can have a dream cut.

The cut of a diamond is one of the four factors that determines the value of the stone.