Diamond

General

Category                   Native Minerals

Chemical formula          

 

Identification

Molecular Weight           12.01 u

Color                      Typically yellow, brown or gray to colorless. Less often in blue, green, black, translucent white, pink, violet, orange, purple and red.

 

Crystal habit              Octahedral

Crystal system             Isometric-Hexoctahedral (Cubic)

Cleavage                   111 (perfect in four directions)

Fracture                   Conchoidal (shell-like)

Mohs Scale hardness        10[1]

Luster                     Adamantine[1]

Polish luster              Adamantine[1]

Refractive index           2.41752.4178

Optical Properties         Singly Refractive[1]

Birefringence                     None[1]

Dispersion                 0.044[1]

Pleochroism                None[1]

Ultraviolet fluorescence   Colorless to yellowish stones; inert to strong in long wave, and typically blue. Weaker in short wave.

 

Absorption spectra        In pale yellow stones a 415.5 nm line is typical. Irradiated and annealed diamonds often show a line around 594 nm when cooled to low temperatures.

Streak                     White

Specific gravity           3.52 (± 0.01)[1]

Density                    3.5-3.53 g/cm³

Diaphaneity                             Transparent to sub-transparent to translucent

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“Overall” Cut Grade

1A grade: All characteristics are best when 1A, but may include a single 1B characteristic. You pay a premium for this cut and you should insist on getting exactly what you are paying for.

 

1B grade: All characteristics need to be all 1B or 1A to 2B. Only a single class 2 characteristic is permitted. The class 2 characteristic should be within 2% or 2 degrees of the 1B characteristic.

 

2A grade: All characteristics need to be 2A or 1A thru 2B. Only a single 2B parameter is permitted and it must be within 2% or 2 degrees of the 2A characteristic. (crown angle degree rounds only)

 

2B grade: All characteristics need to be all 2B or 1A thru 3A. Only a single 3A characteristic is permitted and the 3A characteristic cannot be a very thick girdle or more than 1 degree too shallow a crown angle. The 3A characteristic must be within 2% or 1 degree of the 2B characteristic. (crown angle degree rounds only)

 

3A grade: A stone may be all 3A or 1A thru 4A. Any characteristics of 4A must be within 2% or 1 degree the 3B characteristic. More than a single 4A characteristic and the stone cannot grade 3A. An overall class 4 girdle thickness cannot grade 3A overall. An overall girdle thickness is NOT determined by a single thin or thick area of a girdle. “Overall” has a meaning equivalent to “the major portion.” (crown angle degree rounds only)

 

3B grade: As stone may be all 3B or 1A thru 4B. Any single characteristic of grade 4B must be within 2% or 1 degree of the 4A measurement. Only one class 4 characteristic permitted. Stones with class 4 extremely thick or extremely thin over all girdles may not be graded overall 3B. (crown angle degree rounds only)

 

4A grade: A stone may be all 4A or 1A thru 4B. Only two 4B characteristics are permitted at most. (crown angle degree rounds only)

 

4B grade: Is all 4B or may be any combination from 1A thru 4B. Stones with more than two 4B characteristics are automatically 4B.

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5 Reasons to Get a “Good” Appraisal

 

1. The end result of every appraisal must be to come to logical, supported result. You can’t just use the most convenient appraiser. Its like looking for a doctor to do important surgery. You must try to find the best one available. With medicine, it may be your life. With jewelry and diamonds, it is definitely your wallet.

 

2. Appraisers discover and disclose inherent vice. Insurance companies may choose not to cover your loss if they feel there was some weakness in the gemstone that was there all along. This is what they call “inherent vice’. We search for these problems and advise you, in advance, of damage. Then you can make an informed decision about purchasing the gem.

 

3. We have years of experience dealing with consumer’s needs and insurance company requirements. We will supply you the required materials as a matter of course.

 

4. A good appraisal will give you an adequate description to replace missing elements when you have a partial loss. One line appraisals just can’t provide enough detail to describe side stones or mounting details. We do.

 

5. Whether you require a fair division of your assets due to divorce or estate settlement reasons, or an appraisal for insurance, verifying a potential local or Internet purchase, you need reliable and credible documentation to make the situation finalized in the least costly and fairest way. We won’t take sides and refuse work where clients or vendors feel the need to pressure us into an advocacy position.

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Carat

The carat weight measures the mass of a diamond. One carat is defined as 200 milligrams (about 0.007 ounce avoirdupois). The point unitequal to one one-hundredth of a carat (0.01 carat, or 2 mg)is commonly used for diamonds of less than one carat. All else being equal, the price per carat increases with carat weight, since larger diamonds are both rarer and more desirable for use as gemstones.

 

Clarity

Clarity is a measure of internal defects of a diamond called inclusions. Inclusions may be crystals of a foreign material or another diamond crystal, or structural imperfections such as tiny cracks that can appear whitish or cloudy. The number, size, color, relative location, orientation, and visibility of inclusions can all affect the relative clarity of a diamond. The Gemological Institute of America (GIA) and other organizations have developed systems to grade clarity, which are based on those inclusions which are visible to a trained professional when a diamond is viewed under 10x magnification.

Color

A chemically pure and structurally perfect diamond is perfectly transparent with no hue, or color. However, in reality almost no gem-sized natural diamonds are absolutely perfect. The color of a diamond may be affected by chemical impurities and/or structural defects in the crystal lattice. Depending on the hue and intensity of a diamond’s coloration, a diamond’s color can either detract from or enhance its value. For example, most white diamonds are discounted in price as more yellow hue is detectable, while intense pink or blue diamonds (such as the Hope Diamond) can be dramatically more valuable. The Aurora Diamond Collection displays a spectacular array of naturally colored diamonds.

Cut

Diamond cutting is the art and science of creating a gem-quality diamond out of mined rough. The cut of a diamond describes the manner in which a diamond has been shaped and polished from its beginning form as a rough stone to its final gem proportions. The cut of a diamond describes the quality of workmanship and the angles to which a diamond is cut. Often diamond cut is confused with “shape”.

 

The techniques for cutting diamonds have been developed over hundreds of years, with perhaps the greatest achievements made in 1919 by mathematician and gem enthusiast Marcel Tolkowsky. He developed the round brilliant cut by calculating the ideal shape to return and scatter light when a diamond is viewed from above. The modern round brilliant has 57 facets (polished faces), counting 33 on the crown (the top half), and 24 on the pavilion (the lower half). The girdle is the thin middle part. The function of the crown is to diffuse light into various colors and the pavilion’s function to reflect light back through the top of the diamond.

 

Shape

Diamonds do not show all of their beauty as rough stones; instead, they must be cut and polished to exhibit the characteristic fire and brilliance that diamond gemstones are known for. Diamonds are cut into a variety of shapes that are generally designed to accentuate these features.

 

Quality

The quality of a diamond’s cut is widely considered the most important of the four Cs in determining the beauty of a diamond; indeed, it is commonly acknowledged that a well-cut diamond can appear to be of greater carat weight, and have clarity and color appear to be of better grade than they actually are. The skill with which a diamond is cut determines its ability to reflect and refract light.

Process

The process of shaping a rough diamond into a polished gemstone is both an art and a science. The choice of cut is often decided by the original shape of the rough stone, location of the inclusions and flaws to be eliminated, the preservation of the weight, popularity of certain shapes amongst consumers and many other considerations. The round brilliant cut is preferred when the crystal is an octahedron, as often two stones may be cut from one such crystal. Oddly shaped crystals such as macles are more likely to be cut in a fancy cutthat is, a cut other than the round brilliantwhich the particular crystal shape lends itself to.

 

Light performance

In the gem trade the term light performance is used to describe how well a polished diamond will return light to the viewer. There are three light properties which are described in relation to light performance; brilliance, fire, and scintillation. Brilliance refers to the white light reflections from the external and internal facet surfaces. Fire refers to the spectral colors which are produced as a result of the diamond dispersing the white light. Scintillation refers to the small flashes of light that are seen when the diamond, light source or the viewer is moved. A diamond that is cut and polished to produce a high level of these qualities is said to be high in light performance.

 

 

Fluorescence

About a third of all diamonds will glow under ultraviolet light, usually a blue color which may be noticeable under a black light or strong sunlight. According to the GIA, who reviewed a random sample of 26,010 natural diamonds, 65% of the diamonds in the sample had no fluorescence. Of the 35% that did have fluorescence, 97% had blue fluorescence of which 38% had faint blue fluorescence and 62% had fluorescence that ranged from medium to very strong blue. Other colors diamonds can fluoresce are green, yellow, and red but are very rare and are sometimes a combination of the colors such as blue-green or orange. Some diamonds with “very strong” fluorescence can have a “milky” or “oily” look to them, but they are also very rare and are termed “overblues.” Their study concluded that with the exception of “overblues” and yellow fluorescent diamonds, fluorescence had little effect on transparency and that the strong and very strong blue fluorescent diamonds on average had better color appearance than non-fluorescent stones. Since blue is a complementary color to yellow and can appear to cancel it out, strong blue fluorescence had especially better color appearance with lower color graded diamonds that have a slight yellowish tint such as “I” color or “J” color but had little effect on the more colorless “D” through “F” color grades.

 

Cleaning

Cleanliness significantly affects a diamond’s beauty. A clean diamond is more brilliant and fiery than the same diamond when it is “dirty”. Dirt or grease on the top of a diamond reduces its luster. Water, dirt, or grease on the bottom of a diamond interferes with the diamond’s brilliance and fire. Even a thin film absorbs some light that could have been reflected to the viewer. Colored dye or smudges can affect the perceived color of a diamond. Historically, some jewelers’ stones were misgraded because of smudges on the girdle, or dye on the culet. Current practice is to clean a diamond thoroughly before grading its color.

 

Symbolism and lore

A diamond gives victory to he or she who carries it bound on his left arm, no matter the number of enemies.

Panics, pestilences, enchantments, all fly before it; hence, it is good for sleepwalkers and the insane.

It deprives lodestone and magnets of their virtue (i.e., ability to attract iron).[11]

Arabic diamonds are said to attract iron greater than a magnet.

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Timeline

This is a timeline of jewellery production from the first uses of metal in history to the Renaissance.

7000 BC – Uses of copper in Anatolia, Iran and Eastern Europe.

5000 BC – Uses of copper in Egypt.

4000 BC – Smelting technology for copper in Egypt and Iran.  

3450 BC – Use of natural zinc/copper alloy in Egypt.

 

3500 BC – Gold makes an appearance in Egyptian jewellery.

 

3000 BC – Egypt and Iran makeing simple hammered iron beads

 

3000 BC – The Middle East employ semi-mass-production

 

2000 BC – First signs of the swagging technique

 

2600 BC – Beaded wires began to be used.

 

2500 BC – Egyptians using copper/lead alloys.

 

2500 BC – True iron production technology in Near East.

 

2500 BC – The intentional addition of silver and copper to gold.

 

2500 BC – Gold wires are characterised by seam lines that follow a spiral path along the wire.

 

2000 BC – Use of patterned punches

 

1500 BC – Earplugs and earrings become popular in Egypt.

 

1400 BC – Egypt Amarna period, using resin and mud for repoussé backing.

 

1400 BC – Deliberate addition of zinc to copper in Canaan.

 

1400 BC – Philistines have iron.

 

1400 BC – Very copper rich gold alloys popular in Egypt.

 

1000 BC – Persian sheet bronze work 0.05mm thick.

 

1000 BC – The start of true engraving.

 

900 BC – The Greeks have iron.

 

700 BC – World’s oldest coinage in Lydia.

 

575 BC – In Greece, jewellery is still very rare.

 

500 BC – Hafted hammers were being used in some parts.

 

500 BC – Iron in use in Britain

 

400 BC – Greeks using Beeswax for filler in repoussé.

 

350 BC – Use of combined punches and dies of bronze.

 

325 BC – Animal or human-headed hoop earrings were popular.

 

300 BC – Diadems are first seen.

 

300 BC – Red Coral popular in Celtic jewellery.

 

AD 50 – Start of the Roman period, where addition of silver to gold becomes almost unknown.

 

AD 100 – Sulphur fills hollow gold items throughout the Roman Empire.

 

AD 150 – Tin rings found in Nubia

 

AD 300 – Lead becomes more common in places.

 

AD 400 – Pewter jewellery is made.

 

AD 400 – A shale die is found in Britain.

 

AD 1500 – The Renaissance

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