Sunday, May 24, 2009

General Information

  • Value

    The value of a gemstone is directly related to it's rarity. The size or weight of the stone, it's color and clarity are all valued ultimately on rarity. Colorless diamonds for example, are valued more highly than yellow or brown diamonds, simply because colorless diamonds are more rare. Larger stones are valued higher than smaller stones, simply because larger stones are harder to find than smaller, and generally are more costly per carat. Supply and demand also have an effect on value. Many gemstones are found only in places where the climate (physical, economical and political) is hostile or unstable. This directly affects supply, and as a supply of a gemstone dwindles, it becomes harder to find.

  • Photographs and descriptions.

    We make every attempt to ensure that the photographs and descriptions of gemstones are as accurate as possible, however no photographic process or digital scanner is perfect. The photographs however, in GIF format cannot hope to match the beauty of seeing the gemstone in person. What this means, is that if the gemstone looks good here in a GIF file, it will look great when it arrives at your door. The gemstones as pictured are not to scale.

  • Color and clarity grading.

    As part of the description, most of the gemstones listed have a description of it's color and clarity. Color is described in terms of tone (brightness), saturation and one of 31 hue descriptions as used by the

    • Tones (shown here in blue) are described as:
      Colorless
      Extremely Light
      Very Light
      Light
      Medium Light
      Medium
      Medium Dark
      Dark
      Very Dark
      Extremely Dark
      Black
    • Saturation (shown here in blue) is an indication of how "strong" or "vivid" a color is. Saturation is listed as
      Gray
      Grayish
      Slightly Grayish
      Very Slightly Grayish
      Moderately Strong
      Strong
      Vivid
      The term "Brownish" can be substituted for "Grayish" with colors of a orangish hue.
    • Hues are described as:
      Red
      Orangy Red
      Red-Orange or Orange-Red
      Reddish Orange
      Orange
      Yellowish Orange
      Orangy Yellow
      Yellow
      Greenish Yellow
      Yellow-Green or Green-Yellow
      Strongly Yellowish Green
      Yellowish Green
      Slightly Yellowish Green
      Green
      Very Slightly Bluish Green
      Slightly Bluish Green
      Strongly Bluish Green
      Green-Blue or Blue-Green
      Very Strongly Greenish Blue
      Greenish Blue
      Very Slightly Greenish Blue
      Blue
      Violetish Blue
      Bluish Violet
      Violet
      Bluish Purple
      Purple
      Reddish Purple
      Purple-Red or Red-Purple
      Strongly Purplish Red
      Slightly Purplish Red
      Red

      Some exceptions to these hue descriptions are made with gemstones that are brownish, or pinkish. Orangy pinkish is sometimes described as "peachy".

    • Clarity is a subjective term, however the following is how we describe clarity:
      • Opaque, meaning the stone will not transmit light through it.
      • Translucent, or cloudy, meaning that the stone transmits light, but you cannot see clearly through it.
      • Heavily Included, meaning that the stone is transparent, but the stone is littered with inclusions, which are very visible without magnification.
      • Moderately Included, meaning that the stone is transparent, but there are several inclusions, which are visible without magnification.
      • Slightly Included, meaning that the stone has some very minor inclusions which may be visible without magnification.
      • Very Slightly Included, or eye-clean, meaning that the stone has some very minor inclusions that are not readily visible without magnification. Some inclusions may be visible without magnification once you see them under magnification and know exactly where to look.
      • Very Very Slightly Included, meaning that the stone has some very very minor inclusions which are difficult to see under magnification.
      • Loupe clean, or clean, meaning that no inclusions were seen using 10x magnification. However the stone was not examined microscopically. The stone may be internally flawless or flawless.
      • Internally Flawless, meaning that the stone was examined under a microscope of at least 40x magnification, and no inclusions were seen. The stone has some external blemishes.
      • Flawless, meaning that the stone was examined under a microscope of at least 40x magnification, and no inclusions were seen and stone has no external blemishes.

    • Common Terms

      • Blemish, an defect in a gemstone found at the surface, such as a pit, nick, scratch, chip or even an extra facet where none should be. A blemish differs from an inclusion, which is internal to the gemstone.
      • Calibrated, a gemstone whose dimensions are a standard (mm) size, and are cut to fit ready made jewelry pieces. See our list of calibrated gemstones. For more information, consult our metric conversion information.
      • Carat (ct.), unit of weight. 1 carat is equivalent to 0.2 grams. Carat weight should not be confused with the term karat (kt.), which is used to measure the quality of gold, nor carrot which refers to a plant. The abbreviation (cwt.) is used to indicate the total weight of two or more gemstones, such as the weight of a parcel of stones, or a pair of stones often traded as a group. Carat weight should not be used to judge the size of a stone, as differences in cutting and the depth of a stone can allow stones of the same weight to have different dimensions. Also, the density, or specific gravity of different materials can have the same effect. A one carat sapphire for instance is much smaller than a one carat opal. When looking for a setting for a particular gemstone, the stones dimensions in millimeters should be used, not the carat weight.
      • Grain, unit of weight, 1 grain is equivalent to 0.32399455 carats, or 1/24 pennyweight. The term is sometimes used to approximate a quarter carat.
      • Gram, unit of weight in the Metric system. 1 ounce (avdp.) is equivalent to 28.349523 grams (141.747615 ct.). Rough (uncut) material is often sold by the gram, whereas cut or finished gemstones are generally sold by the carat.
      • Hardness, measured by the Mohs scale (1-10), after the mineralogist Friedrich Mohs (1773-1839).
        1. Talc
        2. Gypsum
        3. Calcite
        4. Fluorite
        5. Apatite
        6. Orthoclase
        7. Quartz
        8. Topaz
        9. Corundum
        10. Diamond
      • Inclusion, an inclusion within a gemstone is an internal flaw, or included crystal, bubble, cloud, graining, fracture, etc.. Inclusions are differnt from blemishs, which are imperfections at the surface of the gemstone. Inclusions are not always bad. Inclusions can be used like a finger print, to identify diamonds and other valuable gemstones. Inclusions can often be used to tell the difference between natural and synthetic gemstones, and in some types of gemstones, the inclusion can even pinpoint the source of the natural stone. In some cases, inclusions can actually increase the brilliance of a gemstone. Beware of emeralds and rubies which do not contain inclusions, as these are extremely rare, and are probably synthetic.
      • Karat (K or Kt.), a measure of the amount of gold present in a gold alloy, expressed in 1/24ths. An alloy under 10 Kt. gold is not legally called gold in the U.S. (9 Kt. in England). The number in parentheses in the table below indicates a marking that is found on some foreign manufactured jewelry, expressed in thousandths.
        • 10 kt. is 10/24 or 41.60% gold (416).
        • 12 kt. is 12/24 or 50.00% gold (500).
        • 14 kt. is 14/24 or 58.33% gold (585).
        • 18 kt. is 18/24 or 75.00% gold (750).
        • 24 kt. is 24/24 or 100% "solid" gold (usually 99.999%).
      • Kilogram (kg.), a unit of weight equivalent to 1000 grams, or 2.2046226 pounds (avoirdupois), or 32.150737 troy ounces.
      • Loupe, a small magnifying lens, usually 10x magnification.
      • Melee, also known as an accent stone, a small round gemstone, usually less than 4mm in diameter. Melee stones are placed around a larger center gemstone to accent it, and make the center stone or jewelry piece appear larger. Melee diamonds may have fewer facets than a standard round brilliant cut.
      • Millimeter (mm.), a measure of distance in the Metric system. 1 inch is defined as 25.4 millimeters. The metric system is the standard used in the jewelry industry, by gemologists, and by science worldwide. For more information, consult our metric conversion information.
      • Ounce (oz.), a particularly confusing set of units, used to measure weight and volume. There are two versions of ounces for weight, troy (also called apothecaries) and avoirdupois (common ounce). There are also two versions of the fluid ounce, used to measure volume, the british fluid ounce, and the U.S. fluid ounce. To add to the confusion, a troy pound is 12 troy ounces, whereas the avoirdupois (common pound) is 16 avoirdupois ounces. When measuring the weights of precious metals, the troy ounce is the standard used.
      • Pennyweight (dwt.), a measure of weight, used to weigh precious metals. 1 pennyweight is equivalent to 1/20 ounce (troy), or 24 grains, or 1.55517384 grams, or 7.7758692 carats.
      • Point, unit of weight. 1 point is equivalent to 0.01 (1/100) carats. The term point should not be confused with the number of facets that a gemstone may have.
      • Precious Stones, an obsolete term which generally is used to refer to diamond, emerald, sapphire or ruby.
      • Semi-precious Stones, also an obsolete term used to describe gemstones which are not diamond emerald, sapphire or ruby. These terms are misleading as many "semi-precious" gemstones are extremely valuable, and some "precious" gemstones are of such poor quality that their value is very low.
      • Troy Ounce, a unit of weight, used to measure precious metals and gemstones. 1 troy ounce is equivalent to 1.0971429 ounces (avdp.), or 31.103486 grams, or 155.51743 carats, or 20 pennyweight (dwt) or 480 grains.
      • Troy Pound, a unit of weight, equivalent to 12 troy ounces.

    • Pearls and Other Organic Gemstones

      Our trade is solely in gemstones and some precious metals. We do not deal in any substance that is of organic origin, such as pearls, amber, coral, shells and ivory. Several organic gems are illegal and environmentally unethical to sell, and we prefer to stay away from all organic "gems"


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