Buying GIA Certified Diamonds Online


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This page provides comprehensive insights on: 

  • Ways to buy GIA graded diamonds at close to wholesale prices.

  • Overview of how the international diamond trade is structured.

  • Details about seven important factors that affect the prices of diamonds.

The bottom line is that James (for GIA Graded diamonds), (for ideal hearts and arrows cut), Blue Nile (for all jewelry purposes), and Brian Gavin (for AGS Graded diamonds) are the finest websites for buying diamonds or engagement rings.

Best Options for Buying Diamonds Online 

Buying diamonds online can be a safe and pleasant experience if you know what you are looking for and you shop with a trusted vendor. Markups online on Loose GIA Certified Diamonds are as low as 8-10% compared to local retailers. We have seen markups go as high as 150%+ locally. Injustice in our opinion.

We recommend the following four options for sourcing a diamond: 

First Option) we highly recommend James Allen as our favorite online retailer for loose diamonds and engagement rings. James Allen is one of the largest privately-owned diamond companies in the world and has the best customer service in the industry. The company is credited for transforming the diamond industry. Also, they will match prices with all other vendors. Please follow this link to shop at James Allen. 

Second Option) if you are looking for precision ideal supercut diamonds, Whiteflash has an incredible site. They also offer the most designer engagement ring brands, including Tacori, Verragio, and A Jaffe, among others.  

Third Option) if you want the trust and reliability of a strong brand, Blue Nile is the company that has also been credited with changing the diamond industry. It's a giant presence in the online diamond space and as seasoned diamond dealers. We have tremendous respect for the Blue Nile and what it has accomplished over the last decade.  

The fourth Option) if you are looking for an Ideal Cut AGSL Graded Diamond, we recommend Brian Gavin Diamonds. Brian Gavin is a well-known name in the diamond industry and is credited for his contribution to the cut of round-shape diamonds. He is the inventor of the Hearts & Arrows diamond. Brian is a 5th generation diamond cutter.  

Sharif, the owner of Petra Gems, has over a decade of experience in the wholesale diamond industry and has traded millions of dollars’ worth of diamonds. If you want a dedicated, knowledgeable, diamond consultant to work with you, please follow this link to consult with Sharif.

The Internet & GIA Transformed the Diamond Trade 

The diamond industry has evolved and changed significantly over the last two decades, mainly due to technological developments. While traditional brick-and-mortar retailers are not happy about how the trade has evolved, the change is significantly in favor of "consumers" or end-users. How? Because online competition and standardization of the diamond grading system have brought transparency into the industry. In the old days, you were at the mercy of a local dealer for both price and quality. Now, to compare prices all you need to do is review prices on three to four websites. This gives you a good idea of what a competitive price is for a 1 carat round diamond that has G color and VSS clarity and an excellent cut with no fluorescence. As far as grading is concerned, as long as your stone is grading or "certified" by the GIA (the Gemological Institute of America). You don't have to worry if the stone is actually what you thought it would be because the GIA is the most consistent grading lab in the world. Historically, there was no universal standard for grading diamonds, now there is one language and grading system for grading diamonds.


GIA Diamonds

What factors should I take into consideration while shopping for a diamond?

In summary, there are seven important factors that you should consider while buying a diamond, including diamond shape, carat weight, cut, clarity, color, certification, and fluorescence. These are the most important factors that affect the price of a diamond. Please see summarized information below about these seven factors.

Factor 1: Diamond Shape

The shape is how the diamond looks, cut refers to the quality of the craftsmanship in which it was cut for a particular shape such as a round cut or oval cut. The shape of a diamond affects the price because certain shapes need bigger rougher stones than other shapes. For example, a round shaped stone is 20-30% more expensive than a princess cut or cushion cut diamond. It could take a 2 carat rough to make a perfect 1 carat round brilliant cut shaped stone; as opposed to a 1.5 carat rough to make a cushion modified brilliant-cut diamond (a round 1ct. is 6.5mm in diameter, and a 1ct. princess is roughly 5.5mm in diameter). Because of this, round-shaped diamonds are higher-priced than any other shaped diamond.

Factor 2: Diamond Carat Weight

Once you determine what shape diamond you want the next step is to determine how big of a diamond you want. Typically, a diamond is weighed in carats, and each carat is 200 milligram or 0.2 gram. The price of a diamond increases as soon as it reaches a full carat. The bigger the stone the price is multiplied many times over because larger stones are rarer. For instance, if all other factors are considered equal, a 2-carat diamond will cost three to four times the price of a 1carat diamond. This is because a 2-carat diamond is rarer to mine than a 1carat. (How rare diamonds play a major role in how the prices of diamonds are determined). As a tip, if you want to save money, buying a 1.9-carat diamond may be a lot less expensive than a full 2-carat diamond. The price jumps significantly once the diamond reaches a full carat range.

Factor 3: Diamond Cut

The cut of a diamond is extremely critical because it's the only C. The outcome of which is determined by us and the quality of our craftsmanship. The cut of a diamond is complex and there are several factors to consider while evaluating a diamond. GIA assigns a cut grade to round diamonds, but they do not have a standard grading system yet for fancy cut stones such as an oval cut diamond. The GIA doesn't assign cut grades to them. The good news is that we have published detailed articles about each shaped diamond and how to assess their cut. Please refer to these articles for assessing the cut of a stone you are considering. Three important factors to consider about the cut are 1) even in GIA excellent cut round diamonds, there is a way to differentiate between an excellent cut diamond and what we refer to as an “ideal super cut" diamond. The only way to tell the difference is if you are able read its proportions and determine what the ideal proportions are (read our proportions article); 2) in both round and fancy cut stones, the depth and table are the most important factors while determining the quality of a cut followed by the size of the girdle, culet, crown angle, and pavilion. Length to width ratios are also important in fancy cut stones; and 3) dealers tend to cut stones deep to save the rough stones, so  you should avoid a stone that has a high depth. A diamond that has a big table is not recommended because it won't have optimal fire and brilliance.

Factor 4: Diamond Color

Color in diamonds is the second most important C after cut as it affects the whole diamond, not in a particular spot which is often the case with clarity. Color refers to the presence of yellowish hue or tint in a white diamond, and is graded from grade D (colorless) to grade Z (light yellow). D-F grades are considered colorless, G-J are near colorless (however, there is a big difference between G and J color), K to M grades are Faint Yellow, N to R are very light yellow, and S to Z grades are light yellow. We recommend to invest in E-F, G for excellent color and investment purposes as well as for maximizing your budget. Next, H/I diamonds are excellent budget options with J being our lowest recommendation, unless you prefer some yellowish tint in your diamond. If so, then you will want to choose very high clarity K-N color grade diamonds.

Factor 5: Diamond Clarity

The clarity of a diamond is important because it directly affects the brilliance of the stone. If a stone is full of inclusions, the stone won't sparkle and will lack luster, fire, and scintillation. The diamond industry has developed a very sophisticated system for grading the clarity of a diamond; it ranges from Flawless (FL) as the highest and Included 3 (I3) as the lowest. FL and IF (Internally Flawless) are flawless grades.  Very Slightly Included 1 (VS1) and Very Slightly Included 2 (VS2) are almost flawless clarity grades. VS1 and VS2 are after Very Very Included 2 (VVS2) and are often considered as eye clean diamonds. Slightly, Included 1 (SI1) and Slightly Included 2 (SI2) are on the lower end of high quality diamonds and are often considered to be eye clean under 1 carat diamonds. White non-crystal type diamonds must be included in any discussion about one carat diamonds. Spread out across the diamond for the diamond to be considered an eye clean is SI1 grade. Included 1 (I1) and Included 3 (I3) are the lowest clarity graded diamonds. Our considered opinion is that VVS/VS1 are excellent investment grade diamonds. VS2 is preferred from both an investment and budget perspective, and SI1/SI2 need extensive due diligence to be done in above 1 carat diamonds. To ensure that the inclusions do not affect the diamond's brilliance and that the stone is eye clean.

Factor 6: Diamond Fluorescence

Fluorescence is an invisible glow that a diamond emits when it is placed under Ultraviolet rays. It ranges from None to Very Strong blue with Faint, Medium Blue, and Strong Blue in the middle. According to a GIA study,the appearance of under 10% diamonds were the only diamonds affected among all the diamonds that emitted fluorescence. Fluorescence can affect the price of a diamond by up to 25%, and knowing this is important. For details, refer to our article on fluorescence. In summary, it is important to note that fluorescence can be a great alley for people on a budget. It can make H or above color diamonds look whiter than they are since fluorescence is blue and blue is a complementary color to yellow. We think that fluorescence is often a plus in H diamonds and above color grades. But in lower grades D-G, preferably there is no fluorescence; faint is usually a safe grade. If you go with fluorescence in D-G colors, make sure you have a valid return policy. Just in case the diamond is among those 10% percent stones in which fluorescence will affect the appearance of the diamond!

Factor 7: Diamond Certification

It really shouldn't be called diamond certification, but this is how it has become known in the diamond industry. Within the industry, we refer to the "certificates" as grading reports. Many labs that provide grading services on diamonds and natural gemstones, but the best lab is GIA (the Gemological Institute of America) – a non-profit organization dedicated to educating customers about diamonds and other gemstones. AGSL (American Gem Society Labs) are also dependable labs, but we recommend GIA because it's the most consistent grading lab in the world. GCAL is another lab that has shown pretty consistent grading so far (but they have a very small market share). To avoid getting taken advantage of we strongly recommend that our customers always buy diamonds that are graded by GIA. Yes, a dealer would give you a good deal on a stone that is graded by a bogus lab or not graded but he/she would cheat you by selling a stone that is H color as an F color stone or one that has SI1 clarity, but has VS1 clarity. We have completed our summary of the seven important price factors.

What is the most important C, and how do I pick the best stone? Which one do I compromise on?

We recommend a balanced approach, meaning that you should get the best of all four Cs and fluorescence in a diamond within your budget. Size is important, but the quality of the cut should always be prioritized. Color and clarity are also important factors. By a balanced approach we mean that instead of going for a 3 carat SI, I color diamond, it makes sense to go for a well cut 2 carat. Purchase an H VS1 diamond if cost is an issue. However, if you are purchasing a diamond as an investment then we recommend that you purchase a diamond that is very high in all four Cs, but is also easy to liquidate. For example, excellent cut GIA graded round diamonds in the 1-2 carat range, E-G color, VVS/VS clarity, and no fluorescence diamonds are also in high demand. They're also considered an investment grade, so buying that type of diamond is prudent. In larger diamonds, that are 4 and above in carats, everything needs to be assessed on a case by case basis. There isn't a standard approach that we recommend because diamonds are wonders of nature. Each diamond merits its assessment. Please email us for a personal consultation or further questions. Read our detailed articles on shape and the 4Cs to learn more.

The Anatomy of Diamonds

Diamonds are minerals formed in high temperature and pressure conditions which are 100 miles down in the earth and brought up near the surface by dynamic volcanic activity. It is also the only gem made of a single element-carbon. Every diamond is billions of years old, and of all the diamonds mined, only 30% are considered gem quality per the Gemological Institute of America (GIA).

State of The Diamond Trade Globally

In terms of trade, Americans make up 40% of the buyers who purchase gem-quality diamonds. The market share of diamond jewelry is around $82-90 billion worldwide. However, because of the advancement of a systematic diamond grading system, diamonds are slowly being treated as commodities. Their prices are becoming standard similar to gold prices.

Diamond Prices Index:

Petra Gems regularly analyzes the prices of diamonds and provides a comprehensive average estimation of diamond prices in our index. These prices fluctuate monthly and as soon as significant fluctuation is observed, Petra Gems updates its index. A host of factors will affect diamond prices, including market demand and supply. The availability and supply of rough diamonds which are controlled by diamond companies, like De Beers and Alrosa, are also primary factors.


In this article, we have discussed necessary factors customers should consider in buying diamonds. Price and budget must be considered as well in deciding which diamonds to purchase. Customers should only buy diamonds certified by well-known labs then they know they are getting authentic diamonds. Customers should also make sure they are getting the best prices for their diamonds.