Gemstones and Their Meanings
Post on 10-Apr-2015
DESCRIPTIONhttp://www.CHRISTIANCHRISTIANITYLIFEMARRIAGE.COM\To avoid making unwanted and uninformed purchases, improve your knowledge about jewelry starting with the tips below.
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Your Guide to Gems and Jewelryhttp://www.CHRISTIANCHRISTIANITYLIFEMARRIAGE.COM
Table of Contents
Your Guide to Precious Gems and Jewelry Learning the Lingo What About Carats Evaluating Color Judging Transparency and Clarity All About Cuts Learn About Cat's Eye and Stars Pros and Cons of Synthetics What Are the Different Types of Stones Evaluating Gemstones How to Spot Fraud Caring for Your Jewelry Where and How Gemstones Are Mined Buying Wholesale Hand-crafted Jewelry
Learning the Lingo
Jewelry with a Capital J, Understanding Basic Jewelry Terms, Processes, and Techniques
It is easy to feel intimidated and out-of-place when youre visiting a high-class jewelry store for the first time. To avoid making unwanted and uninformed purchases, improve your knowledge about jewelry starting with the tips below. If you speak the same language people in the jewelry industry speak then youll go home with the jewelry piece you want, need, and definitely can afford.
The Meaning of Gemstone
A gemstone may be a rock, mineral, or even a petrified material thats cut and polished to be used for making jewelry. It may even be harvested like pearls or organic material like amber, just as long as it has aesthetic appeal. In the old days, precious gemstones only referred to the Big Three: emeralds, sapphires, and rubies. Everything else was labeled as semi-precious gemstones.
Categories today, however, have changed and expanded to avoid further confusion.
The Ins and Outs of Lapidary
Lapidary refers to the process of cutting and polishing gemstones. Rough materials are left uncut and unpolished. Cobbed materials are referred to as fractured. Materials like silicon carbide and diamond, due to their hardness, are used for cutting gemstones in a progressive abrasion process. Compounds like aluminum and chromium oxide are, on the other hand, used for polishing gemstones.
Common cutting techniques include tumbling, drilling, polishing, lapping, sanding, grinding, and sawing. Cut gemstones are then polished into several forms such as sculptures, intaglios, cameos, mosaics, intarsias, inlays, spheres, beads, cabochons, and faceted stones.
Sawing The main tool used in sawing is a copper or steel blade with diamond grit on the edges. Water or oil is used to eliminate cutting debris and prevent the blade and stone from overheating.
Diamond-impregnated grinding wheels made of silicon carbide are used to grind gemstones and shape them into a pre-form. Liquid substance is also
used to prevent both the stone and tool from overheating.
This process is similar to grinding but uses finer abrasives. It is often performed as a follow-up after grinding for removing scratches caused by the previous cutting technique. For round gemstones, a belt sander may be used to ensure smoother and rounder curves.
A lap, which is a flat disk thats either vibrating or rotating, is used to create flat surfaces rather than round ones. The process however is similar to sanding and grinding.
This technique is used if the lapidarist wishes to create a hole through or in a gemstone. Drilling tools may be rotating or ultrasonic.
A gemstone thats placed in a rotating barrel filled with water and abrasives is tumbled for polishing. These gemstones are usually roughly shaped and the polishing process is gradual and performed with interval washings. Sometimes, vibratory machines are used in lieu of rotating barrels. This way, the barrels vibrate rather than rotate. Tumbling techniques are also used to polish metal jewelry pieces.
Cabbing or cabochon cutting is achieved by gluing or dopping the gemstone into a metal or wooden dopstick or simply holding it in place. The cabbing machine then twirls and creates a round smooth surface top and a flat or slightly rounded bottom for the gemstone. This is usually an alternative to faceting for gemstones that possess too many inclusions.
Gemstones that have faceted forms reflect brilliant color and clarity from all sides and at all light levels. This technique is most suitable for transparent stones. Today, new techniques like grooves and concave facets are used to create new looks for faceted gemstones.
The Importance of Cut and Polish in Gemstones
Cut is one of the all-important 4Cs and is used not only to appraise diamonds but gemstones in general as well. Gemstones are often cut with regard to their size alone. But beautifully cut gemstones take their color into consideration as well.
If you are shopping for faceted gemstones, one way of determining the excellence of its cut is to check if its able to reflect light on a consistent level throughout its surface. Look for symmetrical rather than asymmetrical cuts as well. Lastly, be reminded that cut is different from shape.
Polish is simply adding the final touches to a gemstone. A well-polished gemstone is one with evenly smooth gloss and with no visible scratches on its surface.
What About Carats
Bigger is not Always Better: Understanding How Gemstones are Weighed and Measured
Although bigger seems better and more expensive, its not always so in the
world of jewelry. In fact, size isnt even synonymous with carat weight and you need to keep that in mind when shopping for gemstones.
Carat Weight versus Size
Diamonds and colored gemstones alike are evaluated and appraised according to the 4Cs which are made up by cut, color, clarity, and carat weight. Carat weight is much different from size and definitely more important than the latter. Also, take note that carat is different from karat, which is the measurement unit used for gold. Carat weight uses the abbreviation ct and ct TW for carat total weight.
In the past, carob seeds were traditionally used to measure a gemstones weight because of its uniform shape and size. In 1913, however, the jewelry industry managed to set universal standards for measurement and the carat weight system was born.
One carat is always equivalent to one-fifth or twenty percent of one gram. One carat is made up of one hundred points. As a gemstones weight goes up, so does its value or price per carat.
The way carat weight is discussed is occasionally a cause for confusion.
Remember that a gemstone with .005 ct may be called a half point gemstone. A .25 ct gemstone could be called a quarter carat while a .50 carat gemstone may be referred to as a half carat or fifty points.
Gemstones are often listed according to their size because it is more uniform than carat weight. Two different gemstones may have the same size but different carat weights and consequently, different prices as well.
Factors Affecting Gemstone Carat Weight
A 1 carat ruby is smaller than a 1 carat emerald. This is mainly due to the gemstones specific gravity. A gemstones denseness level can make it carry greater weight even though it has a smaller size than other gemstones with the same carat weight. While carat weight is important for traditional and much-prized gemstones, it tends to lose its significance when it comes to common gemstones with high supplies like blue topaz, citrine, and amethyst. Amethyst, in fact, used to be classified as one of the precious stones but its price went down when loads of shipment arrived from Brazil in the 19th century.
Gem Shape or Cut
The shape and cut can occasionally affect the carat weight. While most jewelry designers cut gemstones with size and carat weight in mind, others place more importance on its aesthetic value and may therefore reduce carat weight and size in favor of improved looks. The same can be said for shape as well.
The table diameter is often considered important only for measuring or evaluating the brilliance of a given gemstone, but what few people realize is that it can affect the gemstones carat weight as well.
Similar to gem cut and shape, if the table diameter is shaped in such a way to maximize its window-like characteristics, carat weight might be consequently sacrificed.
Today, studies show that a lot of gemstones sold on the market are cut to take commercial concerns into consideration. Many of these gemstones report loss in weight of just 10% or lower. Some are even cut to the extent of making them appear bigger as well.
The girdle is the dividing line between a gemstones pavilion and crown or its bottom and top facets. Ideally speaking, girdles must be extremely thin and preferably visible only to the naked eye like a light line. Thick girdles not only reduce brilliance and light yield but negatively affect the gemstones color as well. Girdles are often referred to as edges and they are graded as any of the following: very thin, thin, medium, thick, thick, and very thick. Thin girdles look better, but theyre lighter in weight and easier to chip.
The crown of a gemstone refers to its upper area and position on top of the girdle. Acceptable crown height for gemstones is between 11.0 to 16.2% of the girdle diameter. Greater crown height often means greater carat weight.
The pavilion is the bottom portion of a faceted gemstone. Greater bulge usually means heavier carat weight.
This is the facet at a gemstones tip. Like the girdle, culets are better invisible to the naked eye. It may be sharp or pointed.
Evaluating Color How to Determine the Price Value of Color in Gemstones
Gemstones may come in a rainbow of colors, but the jewelry industry uses a universally defined system to grade it. Color accompanies clarity, cut, and carat weight to make up the 4Cs and can greatly affect the aesthetic value of gemstones.
Many people mistakenly believe that darker is always better, but what they should be looking for is brightness and vividness. Use the following tips to accurately evaluate the color of gemstones by yourself:
Evaluating Color of Gemstones by Using the GIA or Munsell Color Grading System
Although there are many and equally effective color grading systems in use today, the GIA or Munsell System is a good primer to start with. It utilizes a plastic set made up of 324 color pieces to serve as standard references. If a
certain color is found missing from the system, interpolation can be performed to come up with more than 760 additional shades.
The GIA or Munsell system is made ideal for judging the color of gemstones because they are built with 3D plastic pieces that resemble faceted gemstones.
Elements of Color
The color of gemstones should be judged according to the three main elements:
This is the first impression we obtain from viewing colors. It is what makes rubies red, sapphires blue, emeralds green, and amethysts purple. Hues have a natural order and they are red, yellow, green, blue, and lastly purple. Numerous shades can be achieved by mixing together any two of these hues.
Chroma or Saturation
This element refers to the vividness, purity, strength, or intensity of a given color. Gemstones with low chroma are referred to as weak while those with
high levels of saturation are called vivid or strong. Saturation of colored gemstones may be classified as the following in ascending order: grayish or brownish, slightly brownish or grayish, very slightly grayish or brownish, moderately strong, strong, and lastly vivid.
Value or Tone
This is what makes you think of red as light or dark red. Gray as well as black and white are referred to as neutral or achromatic colors because they dont possess any hue. Colors with hues are referred to as achromatic colors. GIA uses a numerical system, with its written definitions, to evaluate neutral and achromatic colors alike. For transparent colored gemstones, however, only grades or tones two to eight are considered.
0 colorless or white 1 extremely light 2 very light 3 light 4 medium light 5 medium 6 medium dark 7 dark
8 very dark
Treatments Used for Changing Colors of Gemstones
When shopping for colored gemstones, another question you should definitely ask and one you couldnt evaluate without a definite honest answer is if the color is natural or applied. There are several commonly used and accepted color treatments that are applied to gemstones in order to change their appearance like heat treatment, irradiation, dyeing, and straining.
This is the most commonly utilized and one of the oldest treatments for modifying the color of gemstones today. This treatment may use temperature ranging from 100 degrees Celsius to more than 2000 degrees Celsius and improves color distribution as well as reducing visibility of flaws.
Low or high electromagnetic waves or energy particles are used to change the color of a given gemstone. Like heat treatment, there is little remaining evidence that could clue a buyer to its use.
With irradiation, certain gemstones have their colors enhanced. Bleached, off-color pearls will obtain a darker tint. Brown or light yellow diamonds can become colored. Light yellow or colorless sapphires may turn yellow to orange, but the change could only last for days. Colorless quartz may turn into smoky quartz. Colorless as well as pale pink and dark blue beryl may become yellow. Time, light, and heat may, however, cause the color for treated beryl jewelry to fade.
Dyeing and Straining
This is the major term used to refer to various techniques utilizing a foreign and differently colored substance to modify the color of a given gemstone. A combination of techniques, like dyeing and clarity enhancement for beryl, may be used to improve overall effects. In coating, the application of a second substance is only done on the surface.
Practice makes perfect so browse jewelry shops to familiarize yourself with the various signs that could alert you to the use of applications and treatments on gemstones.
Judging Transparency and Clarity Understanding the Clarity and Transparency of Gemstones
Clarity, together with cut, color, and carat weight, is one of the four important C's used for evaluating and appraising gemstones. Clarity determines the level of flawlessness of a given gemstone. With great clarity comes great transparency as well. Transparency determines the ability of light to pass through a gemstone and inclusions, which are a no-no in judging quality, can also hinder transparency. Use the following tips to help...