Step 4: Gem Grading Lesson 2 Back to syllabus What are Carats? Carat is one of the four Cs of gemstone grading. In English, that sounds the same as carrot, but we aren’t discussing vegetables. Carat also sounds the same as…

Step 4: Gem Grading Lesson 12 Back to syllabus Until the mid-1900’s, purchasing a diamond was very confusing. Dealers used terms like “AA” and “AAA.” These terms meant nothing to the average consumer and, to make things worse,…

Step 4: Gem Grading Lesson 8 Back to syllabus Clarity grading is one of the Four C’s and its importance cannot be underestimated. However, where understanding clarity grading becomes most important is in sales. Many of your…

Step 4: Gem Grading Lesson 13 Back to syllabus It is less than a century that gemology has been regarded as a science. Thanks to pioneering work by people like Robert M. Shipley Sr. and B. W. Anderson, a level of accuracy and…

Step 4: Gem Grading Lesson 14 Back to syllabus Diamonds come in every color of the rainbow. Our standard white diamonds are either colorless or tinted slightly yellow. All other colors are considered “fancy colors.” Fancy…

Step 4: Gem Grading Lesson 15 Back to syllabus Of the four C’s, cut is the most important. It is the cut, or make, of a gem that determines why one diamond jumps out at you with spectacular fountains of light, while another…

Step 4: Gem Grading Lesson 16 Back to syllabus In 2005, the GIA introduced a new method for grading diamond cut. There are many advantages to the new methodology, not to mention that GIA reports are the most common in the…

Step 4: Gem Grading Lesson 10 Back to syllabus A prerequisite to diamond grading is knowing how to tell diamonds from their lookalikes. It does no good to assign color, clarity, and cut grades to a gem, if you cannot tell if it…

In recent decades, something remarkable invaded the thinking process of the colored stone industry. From dealers to consumers, they all discovered “The Cut.”

Step 4: Gem Grading Lesson 1 Back to syllabus The Diamond Four Cs Standard Until the 1930s, no standards for gemstone grading existed. When the Gemological Institute of America (GIA) instituted the four Cs method for grading…

Step 4: Gem Grading Lesson 6 Back to syllabus Gem carvings vary widely in size, shape, and quality. You can find small, simple carvings with a glued-on bail for just a couple of dollars.  Fine carvings from gem grade material…

Step 4: Gem Grading Lesson 4 Back to syllabus Few gemologists deal strictly with loose stones. Most may occasionally have to grade set gemstones. Mounted stones can’t be graded the same way as loose stones. They require special…

The Gemological Institute of America (GIA) grades the cut of a diamond as either; Excellent (the best grade) Very Good Good Fair Poor (the worst grade) Below are the details that will help you understand GIA’s diamond cut grading…

Many new gemologists buy low-quality gems believing they’ve found a real bargain. However, judging gemstone value is very complex.

Gems are graded by four qualities, known as the “four C’s.” These stand for Color, Clarity, Cut, and Carat, (meaning size.). The first thing a consumer needs to understand is that gemstones are graded by the rarity of their features. Even…

Diamonds are the most popular gem used in jewelry today. They have great brilliance, plus a delightful quality know as dispersion. That is the ability to take in white light and throw back flashes of color or “fire.” Diamonds are graded into…

I don’t agree with the Gemological Institute of America’s (GIA) grading system for colored gems. I don’t believe in creating “types” of gemstone categories and adjusting the grading scale to fit what is most common or what some trade groups want…

What is a Fancy Shaped or Fancy Cut Diamond? When discussing diamonds, a “fancy shape” is anything other than round. Fancy shapes are cut to to obtain maximum yield from odd shaped rough. While less common than an octahedron, many broken…

Colored Stone Grading System I use and recommend my own colored stone grading system. Common Sense Gemstone Grading – by Jeff R. Graham copyright 2007 This is the Gem Institute of America’s colored stone grading system. I have been told by…

Chrome Tourmaline is one of the top commercial gemstones available in the market today. Like all Tourmaline, Chrome Tourmaline sets and wears well in almost any jewelry. Keep in mind that these are my personal opinions and experiences, other…

What do I look for when buying Verdelite (green) Tourmaline? Verdelite Tourmaline is probably one of the most common and used gemstones available in the market today. Like all Tourmaline, Verdelite sets and wears well in almost any…

What do I look for when buying Indicolite (blue) Tourmaline? Indicolite Tourmaline is probably one of the most popular gemstones available in the market today. Like all Tourmaline, Indicolite sets and wears well in almost any jewelry and is…

Like all tourmaline gemstones, rubellite wears well in almost any type of jewelry. This stone’s raspberry-like color draws a great deal of attention. Rubellite is one of the most popular gems on the market today.

On September 9, 2014, the Rapaport Group issued a press release stating, ‘Effective October 1, 2014, EGL will no longer be listed as a diamond grading report on RapNet. This notice applies to all EGL grading reports including EGL International as…

According to the Jeweler’s Vigilance Committee (JVC), FTC guidelines now require accurate and truthful representation about the Grading System (GIA, EGL, etc) used to determine the quality of a diamond. Diamond grading has been much in the…

The Hanneman System A Basic Course The cut grade of any round brilliant diamond can be derived from the knowledge of four measurements, two equations, and a table of 12 numbers. The measurements are total height, diameter, crown angle, and…

Lesson 3: Cut Grade Categories and Taking Out the Garbage Cut Grade Categories Cut diamonds can be fitted into one of five categories. Not renowned for my tact, I simply call them Best, Better, Good, Junk and Garbage. Granted, retailers use more…

Lesson 2: Basic Proportions This is basic geometry, but stick with me. In simple terms, a diamond can be considered as being composed of three components which fit together—a cone, a cylinder and a frustum, i.e., part of a cone shaped solid next…

The Hanneman System A Basic Course The cut grade of any round brilliant diamond can be derived from the knowledge of four measurements, two equations, and a table of 12 numbers. The measurements are total height, diameter, crown angle, and…