Natural Diamond Prices – December 2024
At PriceScope, we remain dedicated to providing timely and insightful updates on the latest trends in the diamond market. Our expert analysis focuses on the economic and social changes shaping…
By Erika W.
Q&A with the Trade – Al Gilbertson
Al Gilbertson kindly took some time to participate in our Q&A with the Trade. We appreciate his personal and detailed responses. Mr. Gilbertson is a Research Associate at the Gemological Institute of America (GIA) in Carlsbad, California. Gilbertson grew up around the lapidary business and has enjoyed an acclaimed career in the gem and jewelry industry, including custom cutting, jewelry sales and management, appraising, consulting and publishing. He has lectured and provided workshops for local and national jewelry and appraisal groups, and written numerous articles on appraising and diamond cut evaluation. Gilbertson worked on the GIA diamond cut grading system that was introduced in 2006. His research focused on the identification of visual aspects of diamond appearance and methods to evaluate and quantify those aspects. He is also the author of American Cut: First 100 Years, which outlines the history of diamond cutting in America.
Questions for Al Gilbertson
What sparked your passion for gemstones and jewelry?
I have to admit that my sheer pleasure of working with gems and minerals of all kinds came from my dad. He loved unearthing and collecting them, fashioning them into jewelry, and sharing his knowledge about them with anyone, especially school children. I grew up digging red horn coral in Utah, collecting boothite specimens in Nevada, and bringing amethyst to the surface at several locations.
I don’t remember when I cut my first stone as a child in the 1950s. My parents opened a lapidary shop in 1960 and I was cutting cabochons on my own by the age of 11. My desire to be able to create the more brilliant gems led me to seek out a mentor (Lois Schumann of Visalia, California) to learn custom faceting. That led to a job for AGS-affiliated McDonald Jewelers in Fresno in the mid-70s as a custom colored gemstone cutter where I worked alongside diamond cutter George Garabedian. I learned a lot from George, the store owner Bill McDonald and Bob Praska. Bill and Bob, both gemologists, finished their GIA classes in the 50s and were my mentors for appraisals, gem identification, diamond grading and jewelry manufacturing. I helped select diamond and colored stone rough that we cut and fashioned into jewelry.
McDonald Jewelers was well known for its custom design jewelry, including a very famous benitoite jewelry suite, and was very proud of the store’s AGS affiliation and their employees’ GIA education. We wove our GIA-acquired knowledge into our sales talks about colored gems and diamonds and used AGS grades on all of our stock and in appraisal reports. McDonald’s was one of a very few AGS stores at the time to do so. Many probably don’t realize that the AGS grading system was started in the mid-1960s and that GIA’s Richard Liddicoat worked with members of AGS to design it. McDonald Jewelers not only encouraged me to take classes offered by GIA, but also reimbursed the cost once I completed them!
I learned very quickly about cut grading of diamonds from Bill and Bob and the classes I took from GIA and AGS (the AGS classes were administered at that time by GIA). It was the perfect environment to absorb gemology and I couldn’t get enough. I was soon a Graduate Gemologist (GG), an appraiser, and later the store manager. I continued cutting gems and have always tried to increase my knowledge of how to cut better-looking gems.
My dad had passed away while I was serving in the Air Force, several years before I went to work in Fresno, and he never saw my return to the industry that he loved. I think he would be pleased that he was able to instill his passion for gems in me.
My wife Laura has always encouraged me and been my inspiration. She loved that I continued to cut gems and worked to understand how to design facet arrangements to enhance a gem’s visual interest. When Bill McDonald decided to retire and sell his Fresno store, we moved to Oregon to be closer to her family in the mid-80s. In Oregon, Marty Zell of Zell Bros Jewelers talked me into working as an independent appraiser for his store. I was soon seeing diamonds larger than I had ever seen before on a regular basis. It wasn’t long before my wife and I were providing appraisal services for more than 50 jewelers throughout the Pacific Northwest. Our reports included diamond cut grading information; for the AGS stores we provided AGS grades, and for non-AGS stores we used the GIA Cut Class system.
While gems were always the focus of my interest, the jewelry that showcased the gems was also quite appealing. For a few years Laura and I owned the trade shop located at Zell Bros, manufacturing some very high-end jewelry.
As someone who has explored many facets of the gem and jewelry industry, what is the common thread that keeps you motivated?
My dad and I dug material out of the ground that we cut and set into finished jewelry, but what we did as “rock hounds” is nothing compared to what it takes to extract fine gem material from the depths of the earth today and place it into someone’s hands as a finished work of art. When I think about what it requires to unearth some of the small baubles we cherish (see http://www.fieldgemology.org/ for examples of this), their true rarity—after all, we can’t just walk into the hills and find these things lying around—and the expertise it takes to create something visually appealing, I get excited. This keeps me motivated.
I have always enjoyed solving puzzles; my interest in appraisals and cut research fulfilled my dreams. As an appraiser, I was lucky enough to see fabulous pieces of art that passed through the hands of J & SS DeYoung, were designed by Harry Winston or various Spectrum award winners, or an obscure designer; all of which pushed me to learn how to unravel their origins. This quest to understand things, dig into vague areas, and tear back the mysteries exposing them to full view seems to be a recurrent theme in my life. It certainly drove me to understand how to evaluate gem cutting, particularly of diamond, and continues to be a prime motivator in many areas of my interests. As an example, this is my motivation to continue to research historic documents (such as the research that led to the American Cut; the First 100 Years). I have a thirst to better understand the monumental efforts of those who went before us. It is exciting to help others discover the origins of the wonderful things we do. Working at GIA, I continue to see rare things, handle them and uncover their secrets…and I get paid for it.
What are your top diamond buying tips for consumers?
When I was an appraiser, people asked me to look at their diamond (ring, pendant, etc.) and tell them if they got a “good deal” or not. This is the heart of my first tip. It is never a good deal unless you love it. Jewelry, especially diamond jewelry, is very personal. Whether we wear jewelry to symbolize a personal relationship or to represent a personal statement, we need to see something in the piece that sparks an emotion deep inside of us. So, rethinking the notion of a “good deal”—it is never a good deal unless you love it and if you love it, what is the real value to you? I have paid more than I should have for a personal item because the piece evoked that emotion. Did I get a good deal? Yes—because I could have never found something as personal and expressive with anything else. Did I also pay above a certain market price? Perhaps, but that is less important to me. So, Tip #1. Only buy it if you love it.
Tip # 2. Do some research. You need to know what constitutes the quality you like before you can safely make a purchase. Let me explain. I used to go to the Tucson Gem Show each February, and was unsure when to buy during the two weeks I was there. In some cases, it was better to do several price comparisons, looking for a particular stone and seeing the price ranges, and only buying after seeing a large sample set from a number of sellers. Later, however, the piece I wanted was sometimes gone because someone else purchased it. On occasion the price was elevated as soon as the seller realized he was selling it too low. There were times when I knew enough about an item that I bought the first one I saw. I did some research and knew what constituted the quality before I made the purchase. If you don’t do your research first, then any claim can be made about an item and you are buying blind. The following tips are all types of research you must do.
Tip #3. Look at diamonds next to other diamonds in different types of lighting. Think about this for a moment. Where will your diamond be worn most of the time? What is the lighting like? Where do you want your diamond to look its best? Diamonds look dramatically different in varied environments and look different to different people. People with very good close-up vision will hold the diamond closer to their eyes, thereby creating a different lighting environment (as they block more light coming to the diamond) than someone who holds it almost at arm’s length to admire it. GIA’s Cut Grading System provides a guide as to what most people prefer—but each person has their own taste.
When we conducted blind observations to understand diamond preference, one gentleman from India liked nothing with a table smaller than 63 percent. He thought all of those smaller-tabled diamonds were ugly and closed looking; most would sharply disagree with him. A cut grading system should only be viewed as a guide and ultimately your personal preferences should be the final criteria.
This is where your research should start. What is it you really like? Without that knowledge, how can you pick a diamond you will love? Another caution here: not all AGS Zero cuts look alike, and not all GIA Excellent cuts look the same as each other. You can’t rely upon a grading report to tell you what it will look like—you have to look at the diamond.
While on the subject of looking at diamonds, let’s talk about cut and those shapes that don’t have a cut grade. How do you know if you are getting something that is well cut? There is some information online, but there are a few things you can do to evaluate the diamond. Obviously, first compare various diamonds of the same cutting style visually. Hold the diamond (face up, tilting it slightly, no more than 10 to 20 degrees) in tweezers over something that is a bright fluorescent color (orange is great). Can you see much color coming through the diamond? This is not a good thing (sometimes a very little color is seen on the corners of squarish cuts and is normal)
Additionally, some cutting styles can have very shallow crowns, and in combination with certain proportions, reflect the girdle into the table when you are looking at them. This is not easily seen by the novice. The problem is that when that diamond is set and dirt gets trapped under the bezel of the mounting on the girdle facet, the reflection that you see in the middle of the stone won’t be very appealing (you’ll see the reflection of the trapped dirt on the girdle). To simulate this, take a black marking pen and carefully color the girdle facet at some small point (this wipes off easily with some acetone or isopropyl alcohol). If you see the ink reflection in the middle of the stone—reject it. Of course there are various diamond viewers out there that can help also.
Tip #4. To avoid buying blind, get familiar with the jargon used by diamond sellers. I would be remiss if I didn’t remind you that GIA’s website has information for consumers as well as websites such as Pricescope. Study online and develop an understanding of terms, and then go out to see what the sellers say. If you want them to be candid with you, say that you’ve been looking and are trying to understand what you’ve been told, but don’t say too much. Let them educate you as to how they look at diamonds. Some jewelers don’t necessarily know as much as some Pricescope regulars, but that doesn’t mean you can’t learn from them and find the diamond you love. Keep the questions simple and straight forward. Those that are just commodity vendors will quickly become apparent, and those you can learn from and have an interest or passion about diamonds will rise to the occasion. Don’t be too quick to judge if they don’t use the same jargon or agree with what you think; just learn from the experience.
Tip #5 is to determine the ranges of quality in each of the Four C’s that you feel are important to you. For example, have you looked at D, G and K color diamonds in different lighting? I’ve met several consumers who like their diamonds to have a warm color (yellowish) and not be completely colorless (very whitish). Additionally, someone with extremely good close-up vision can sometimes see a VS2 inclusion with the unaided eye. Is that distracting? What clarity grades are OK to you? Remember the need to look at a diamond and love it—what do you love and dislike about any stone? What is your preference on shape? Carat weight is the final C that determines cost. So—what are the parameters of each C that you like? Which ones are you willing to sacrifice something to meet your budget?
Tip #6. Get a sense of the cost. You’ve done your research. You have an idea of what you like and don’t like. The internet is a great resource for getting an idea of cost. However, many jewelers have different overheads. Those with a large well-trained staff have to pay them accordingly and may pay for their training. Insurance costs more for a store if they have a larger on-hand stock. Costs aren’t fixed. If you buy from a well-known high-end name brand, you are paying for the overhead, knowledge and expertise, even their name (which implies a certain level of quality). Bargains are not always the bargain you think they are. Don’t believe the hype about getting a great deal. By getting a sense of market prices, you can make an intelligent decision about whether you want to pay a little more from one source (who may provide more information and expertise) than another.
Tip #7. Before you buy, find an independent expert that will verify that the diamond you are buying matches the report and has not been damaged since the report was done. NEVER buy a diamond without a report from a top-tier grading laboratory—GIA, of course. I once examined a diamond for a client who didn’t have the report with them, but had the information from the report. The measurements were close enough to be the same diamond and the clarity grade and weight were right, but it was NOT a Light Fancy yellow color in my mind, it was a Fancy yellow. The client waited for the report and when reviewed, it was obvious that the inclusion in the plot was in a different location. It was not the same diamond. At some point a very similar diamond had been switched and my client had a better diamond. The dealer was able to obtain the original report (which matched) and my client had a very good deal. The switch was inadvertent. There is a lesson here. Just because something isn’t what the seller said, doesn’t mean that they meant to defraud you. Give them the opportunity to correct what might be an unintentional mistake.
Tip #8. Buy a diamond that is inscribed with the report number. (This would have alleviated the problem in Tip #7.) You can see that the inscription number matches the report number from the start. How do YOU know it’s the same diamond 10 years later? This will make it very straight forward. If you take it to someone you don’t know for repair (on a trip you notice the stone is loose and you need it tightened immediately), you can point out the inscription to them when you drop it off (noting the inscription number on your receipt) and have them show it to you when you pick it up.
As one of the first AGS Independent Certified Gemologist Appraisers, what is your checklist for consumers to qualify appraisers? What kinds of questions should consumers ask about their jewelry?
This is only a brief overview of some important points, and the focus will be related to diamonds when necessary or the answer gets extremely complicated. As you should know, anyone can say they are an appraiser, and legally anyone can provide appraisals for many purposes (insurance, etc). It’s surprising how appraisers embellish their experience and supposed credentials (see my suggestions on point 2 below).
A good appraiser will have had a lot of experience in the trade. That doesn’t mean they have enough experience to value certain unusual items. On more than one occasion I was asked to evaluate items I felt I was not qualified to appraise. I turned down those assignments, or with the client’s permission, obtained the assistance of a specialist.
Membership in some organizations can further qualify someone, but just because they belong to a group, have taken their courses, and purport to subscribe to a certain ethics code, does not mean they are a good appraiser. They can be poor at correct identification or value research.
Listed below are some questions that help qualify an appraiser. You should obtain a copy of their professional profile first and try to see how they qualify along these lines:
1. Are you a Graduate Gemologist of GIA (G.G.) or a Fellow of the Gemological Association of Great Britain (F.G.A.)?
2. Are you a member of a professional personal property appraisal organization or other group that qualifies jewelry appraisers?
An example would be the International Society of Appraisers (ISA), the American Society of Appraisers (ASA), National Association of Jewelry Appraisers (NAJA) or the American Gem Society (AGS). Note that all of these organizations will help you find an appraiser in your area. I highly recommend calling a number of the better stores in the area and ask who they can suggest as an independent appraiser. Those answers, along with suggestions from the above organizations, should help qualify someone.
3. What kinds of continuing education do you do each year? Look for examples that are appraisal, gemological and jewelry specific.
4. How do you stay current on industry guidelines and research, along with local and federal laws?
5. What are your specialty areas?
6. What standards do you conform to? Do you write appraisals to the guidelines of the organization(s) that you are a member of?
7. May I see a sample of your appraisals? Will my appraisal have color photographs?
8. What will you use to color grade my diamonds?
A “master set” of diamonds graded by GIA as a “master set” is the best answer.
9. What grading systems do you use when grading diamonds? Have you been trained or attended classes to estimate grades by their cut grading system?
A surprising number of appraisers have not completed classes for assessing diamonds using the newer cut grading systems, so it is an important question to ask.
10. How much do you charge?
A qualified appraiser who is well respected in the area is likely to charge more than someone who has trouble getting much business. Expect to pay more for good expertise.
Below are some questions to ask the appraiser about your diamond jewelry. Note: As tempting as this is, don’t try to test the appraiser. You want them to have as much information about your jewelry and diamonds as possible before they begin their work. This means you should have all previous appraisals and grading reports with you. A good appraiser will be able to compare the reports with the item and determine if there is damage or change of any kind.
I know that some on the Pricescope forum prefer to not show the appraiser this information, but if you have qualified your appraiser first, your real goal is to correctly identify the item and value it—not test your appraiser. If you play this game, don’t be surprised if the appraiser wants an additional fee for adjusting his work after you provide the documentation. Note that the origin of the jewelry can have an impact on value. You will want the appraiser to know who the designer is, if it is custom designed.
Questions to ask:
• Are the mountings in good condition? Are the diamonds secure?
• Is there any evidence of damage?
• Does the appraiser’s examination agree with your original paperwork?
In American Cut, you write about the evolution of diamond cutting. What research are you currently conducting that will impact the future of diamond cut and laboratory grading?
I don’t think any of us can predict what will impact our industry or in what way. Both GIA and AGS taught about an “ideal cut” starting in the 1930s. It is only in recent years that cut quality has had a real impact in the jewelry trade. The polished girdle was patented in 1908, but has only become the most common form of the girdle in the last 20 years. Some things take a long time before they are embraced, while others are never embraced.
Most of what I am working on is confidential for a variety of reasons. We have found that by releasing information about our research before it is complete, the limited information can lead the trade to wrong conclusions. Of course, we are studying a variety of fancy shapes and are always studying ways to improve what we are already doing. Remember that diamond cutting technology is continually evolving. The measurement equipment is getting better, the software to design new cuts is improving, and the various cutting equipment to implement these things are evolving. Changes occur almost on a quarterly basis for diamond cutters. We work at keeping up with these innovations and to understand how they might affect grading.
The newest development that I can talk about is plasma etching. The company doing this only recently finished setting up their facilities and very few have seen a diamond cut with plasma etching. It is quite dynamic. Plasma etching places small areas of diffraction grating (thousands of parallel lines per centimeter) on the surface of the diamond. Diffraction gratings separate white light into spectral colors. Under diffused lighting this effect is weak, but under spot lighting the grating separates spot light sources into distinct bright spectral colors, like those in a rainbow. This adds a lot of fire to the look of a diamond. I see it being used in new cutting styles or with various colored diamonds. This doesn’t mean that everyone will like it, as those familiar with diamonds will feel fire from plasma etching is too strong and that the diamond no longer looks like what they think a diamond should look like.
Could you share about the “Gilbertsonscope” and its relationship to your involvement in AGS’s Cut Task Force?
I won’t explain too much about what some call the Gilbertsonscope since Good Old Gold spent some time documenting its evolution. (http://www.goodoldgold.com/technologies/reflectortechnologies/history/)
I was very active in the American Gem Society and taught a couple of lab sessions and appraisal classes at their conclaves. I was on their ethics and education committees, but most active on their appraisal committee and last year received recognition for 30 years as a CG in AGS. I was also one of the first two ICGAs within AGS.
When AGS was exploring the idea of setting up a laboratory, I served on the AGS Lab Gemological Committee and after the lab started, was asked to be part of the AGS Cut Task Force.
I was doing research on how to use the Firescope™ to evaluate cut and decided a better tool to evaluate cut would be a refinement of the Firescope™ that used colored rings set at different angles. This would tell the scope user where the light that made up different parts of the light return of a diamond was coming from. It was color-coding the light return. I shared my ideas with a number of people including Sergey Sivololenko of Octonus and the AGS Cut Task Force.
GIA asked me to provide a poster session on this subject at their 1999 Symposium. Sergey liked the concept and put it into DiamCalc as a “Gilbertson lighting” environment in early 2000. AGS looked at the idea for some time and eventually used it as part of their research. They adjusted the color bands and named it ASET. Of course, I was soon hired by GIA to work with their cut research.
What advice do you have for Pricescope members who are interested in a career in the gem and jewelry industry?
Your path will be easier if you start with a passion for gems or jewelry, but there are aspects that are central to any career. Education is fundamental. GIA’s on-line courses through the eLearning programs are a great to get gem knowledge. A word of caution here: reading and studying about something does not work as effectively unless you are working in that field. Find a jeweler, wholesaler or diamond cutting company you can work in. Before starting that job, make sure they want their employees to be educated and knowledgeable. You want an environment where your learning will be encouraged. I spent many of my lunch hours at McDonald Jewelers studying or using a microscope to better understand what I was learning.
You have to immerse yourself in the subject. For example, you can’t start successfully appraising without wide experience and you can’t design jewelry without experience in basic metal-smithing. Getting into a firm where you can really learn is probably the biggest hurdle. In this industry, you have to put in a lot of effort and time to really advance.
Do you wear jewelry? What stones and styles do you admire?
My long involvement in the trade and a deep appreciation for so many wonderfully unique and beautiful gems and designs, it is hard to narrow it down to a few and it is always changing as I discover something new. I have a few items that I usually wear—a simple gold wedding band, and a deco-style platinum, hand-chased band with a bezel-set cabochon-cut yellow synthetic Sumitomo diamond that I designed. It is quite simple and subtle in its overall appearance. I occasionally wear my dad’s ring, which features a native cut (Sri Lankan) blue synthetic sapphire in a classic 50s fluted style. As jewelry is personal, all of these mean something special to me. I occasionally wear a few other items I designed and have cut the stones.
Special thank you to:
Al Gilbertson, Research Associate, Gemological Institute of America
Discuss this Q&A with Al Gilbertson on the forum
