Diamond

Cut refers to the shape of the diamond. The diamond's proportions, polish, and symmetry is tightly linked with its sparkle, brilliance, fire, and scintillation. A poorly cut diamond can appear dull and lifeless. It is essential for a diamond to have well-cut angles and finish for it to sparkle and allow maximum reflection of light. An excellent cut will maximize these characteristics and allow you to create an enduring piece of jewelry that makes a statement.

In diamond cut grading, a diamond is graded on the quality of its shape, rather than its carat weight. Diamonds are graded on a scale from Poor to Ideal, with the ideal being the rarest. Diamonds that are cut poorly can appear dark and lifeless. A poorly cut diamond will also be dull, while well-cut diamonds sparkle brightly. This is hugely important in determining diamond beauty and value.

1. Ideal: Highly reflective and proportionally polished. A diamond's brilliance and fire are determined by the precision of its cut. In 17th-century Europe, diamond cutters perfected a method of dividing the stone into different shapes and angles in order to maximize light refraction without losing any of the rough material. Today, this practice is named “Ideal” (or “Ideal-Cut”) because these cuts are still considered the best way to cut a diamond for maximum brilliance and fire. The history and definition of the ideal cut is a fascinating story of intrigue and rivalry. The Belgian diamond cutter Marcel Tolkowsky coined the term ideal cut in 1924 when he published his landmark book "Polished Diamonds, How to Choose and Buy Them." Tolkowsky was an innovator who changed forever how diamonds are cut. Before him, diamonds were cut in whatever fashion by the cutter; after him, all diamonds are measured with precision and then customized for each stone to maximize its brilliance.
2. Excellent: Highly reflective and proportionally polished. A diamond with a cut grade of Excellent is extremely brilliant. It displays a consistent pattern with strong light-to-dark contrast, making the reflections look clear and balanced.
3. Very Good: Mediocre Polished diamonds those have less brightness and brilliance than the excellent cut diamond.
4. Good:  Poorly cut diamonds with lower proportions and scintillation. That have significant lesser light reflection property.
5. Fair:  Very poorly cut Diamonds that look mostly dark and lack of contrast. 

Almost all diamonds contain "birthmarks," which are small imperfections inside or on the surface, as they are formed deep within the earth under extreme heat and pressure. Diamond clarity refers to the presence and visual appearance of internal characteristics of a diamond called inclusions. These inclusions are also surface flaws called blemishes within a diamond caused during its formation or the cutting process.

Several factors affect the clarity of diamonds, such as their size, relief, nature, and position, as well as how these factors affect their appearance. Its value increases the closer it gets to perfection, even though no diamond is perfectly pure.

Inclusion

In the process of emerging under such enormous pressure, tiny defects appear in the crystal structure. These internal blemishes are called inclusions, and the more inclusions a diamond has, the poorer the diamond. Most inclusions found in gem-quality diamonds do not affect the diamond's performance or structural integrity and are invisible to the naked eye (they are magnified 10X when the diamond is graded). Inclusions can be foreign objects or crystals of other diamond crystals, or they can be structural defects such as tiny cracks that appear whitish or cloudy. Large clouds can affect a diamond's "sparkle," or ability to transmit and scatter light. Large cracks near or on the surface can reduce the diamond's fracture toughness. There are different classifications of inclusion types, mainly including: 

• Feathers 
• Needle
• Crystal
• Black minerals or crystal
• Knot
• Cavity
• Cleavage
• Chip
• Internal graining
• Pinpoint
• Laser Drill hole 
• Surface blemishes

Blemishes are blemishes that appear on the outer surface of a diamond after it has been formed during the process of cutting, setting, and wearing and polishing the diamond. Extra facets, polish lines (thin parallel grooves and ridges), or burns (overheating on the polishing wheel during cutting) are examples of defects introduced during manufacturing to improve a gemstone's clarity. Scratches, nicks, nicks, and scuffs are examples of imperfections that can occur in a diamond during handling, setting, or wearing. Cuttings are shallow holes where the diamond has partially broken off, usually at the edge of the girdle. Some terms related to types of blemishes are:

• Polish lines
• Grain boundaries
• Naturals
• Scratches
• Nicks
• Pits
• Chips
• Breaks
• Dark spots
• Light spots

All of these factors are considered together as gemstones need to be graded based on their overall appearance. Once these questions are answered, the diamond can be given a clarity grade. In the rarest and most expensive diamonds, inclusions are too small to be seen in good light even under 10x magnification, which is why these diamonds are called "flawless" after the Gemological Institute of America (FL ) or "Internally Flawless" (IF) due to the US Quality Analysis System. At the other end of the scale are "imperfect" stones (Grade I), with obvious blemishes that detract from their natural beauty.

GIA Diamond Grading System 

•  FL (Flawless) - No external markings or internal inclusions visible to the trained eye at 10X magnification. 
•  IF (Internal Flawless) - Under 10x magnification the trained eye has only minor surface imperfections but no internal inclusions. 
• VVS1, VVS2 (Very, Very Slight Inclusions) - Few, very small inclusions and/or surface imperfections difficult to see with the trained eye under 10x magnification. Typical defects are tiny dots, faint clouds, tiny feathers or internal particles. 
• VS1, VS2 (very small inclusions) - very small inclusions and/or surface blemishes difficult to see with the trained eye under 10x magnification. Typical blemishes are crystals, feathers, pronounced clouds and pinpointclusters. o SI1, SI2 (Slightly Included) - Small inclusions and/or surface blemishes easily visible under 10x magnification but invisible to the trained eye. Typical defects are crystals, moire and feathers.
• I1 (Imperfect 1) - Inclusions and/or surface blemishes visible under 10x magnification but difficult to see with the naked eye. Has little effect on the brilliance of the stone.
• I2 (Imperfect 2) - More and/or larger inclusions and surface imperfections are easily seen without 10x magnification. The brilliance inside the stone has faded a bit. 
• I3 (Imperfect 3) - Many and/or very large inclusions and surface defects that are easily visible without 10x magnification. The severity of the inclusion will obviously destroy the gemstone. Rarely used in jewelry (mostly as industrial diamonds). But these days they are also very popular for their unique and unusual look.

 Diamonds range in color from D (colorless) to Z (dark/colored, such as yellow or brown). While many people think of gem quality diamonds as colorless, truly colorless diamonds are actually very rare. Most diamonds used in jewelry are almost colorless with yellow or brown tinges.  Color grades are determined by comparing each diamond to a standard set. Each letter grade represents a color range and is a measure of how perceptible a color is.  Fluorescence - Some diamonds emit visible light when exposed to ultraviolet radiation, but fluorescence is not a factor in determining color or clarity grades. However, diamond grading reports often describe its intensity and color as additional distinguishing characteristics. 

 An important factor in a diamond's value is its weight. The word "carat" comes from the seeds of the carob tree used in ancient times to balance scales and is the unit of choice for measuring the weight of diamonds.  One carat equals 200 milligrams or 0.007055 ounces. The standard system of metric carats is further divided into 100 points. A 50-point diamond is half a carat, or 0.5 carats. 

 A carat is a measure of the actual weight of a diamond. According to GIA, one carat is equal to 0.2 grams, which is about the weight of a paper clip. Of course, the larger the carat, the more expensive the diamond. Since no two diamonds are exactly alike, carat should be used as a guide, as it only determines a diamond's weight and not its actual size.