Learn How to Buy Loose GIA Certified Diamonds Cheap

The bottom line is that James is our number one pick for buying loose GIA certified diamonds and engagement rings. The company is a pioneer in developing the ideal technology for showcasing diamonds in super HD videos. They also offer the most competitive prices in the industry and have unmatched customer service. The long-term benefits and support are also a great add-on.   

James Allen

Best Options for Buying GIA Certified Diamonds Online: 

Buying diamonds online can be a safe and pleasant experience if you know what you are looking for and by shopping with a trusted vendor. Markups online on loose GIA certified diamonds are as low as 10-20% compared to local retailers. Markups can go as high as 150%+ locally.

We recommend the following four options for buying a GIA or AGS certified diamond: 

First Option) we highly recommend James Allen as our favorite online retailer for loose GIA certified diamonds and engagement rings. James Allen is one of the largest 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 cut diamonds, Whiteflash is an incredible company. They also offer 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 credited with changing the diamond industry as a whole. It has significant influence within the diamond industry. We deeply respect Blue Nile for what it has accomplished over the last decade.  

The fourth Option) if you are looking for an ideal cut AGL 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 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.  

GIA Diamonds

Factors to Consider While Shopping for a GIA Certified Diamond:

In summary, there are seven important factors to 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.

Here is a summary of what should be taken into consideration under each factor:

Factor 1: Diamond Shape

The shape is how the diamond looks, cut refers to the quality of the craftsmanship while cutting a diamond into a particular shape e.g. a round cut or an oval cut. The shape of a diamond affects its price because certain shapes need bigger rough stones than others. For example, a round shaped diamond is 20-30% more expensive than a princess cut or cushion cut diamond.

It could take a 2 carat rough diamond to cut a perfect 1 carat round brilliant cut while it might take 1.5 carat rough diamond to cut a princess cut diamond --- a round 1ct. is 6.5mm in diameter and a 1ct. princess cut is roughly 5.5mm in diameter. As result of the size difference, round cut diamonds are priced higher compared to other shapes. 

Factor 2: Diamond Carat Weight

After determining the shape of a diamond, the next step is to learn about the carat weight of a diamond. Typically, a diamond is weighed in carats, and each carat is 200 milligram or 0.2 gram. The price of a diamond increases significantly as soon as it reaches a full carat. Once a diamond reaches the 2-3 carat range, the price is multiplied by many times over because larger stones are rare and therefore more expansive. For instance, if all other factors are considered equal, a 2-carat diamond will cost three to four times the price of a 1-carat diamond. This is because a 2-carat diamond is rarer to mine than a 1-carat diamond.

Tip: if you want to save money, buying a 1.9-carat diamond may be 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 important because it is the only C the outcome of which is determined by a cutter and not nature. 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 for fancy cut stones yet. As result, GIA doesn't assign cut grades to them.

The good news is that we have published detailed articles about each shape and how to assess their cut. Please refer to these articles for assessing the cut of a diamond before buying it. For example, check our guide on oval cut diamonds before buying an oval shape diamond. 

Tip: 1) even among 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 best way to differentiate between them is by thoroughly analyzing the cut proportions of the diamond (read our ideal cut proportions article); 2) in both round and fancy cut diamond, 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 diamonds; and 3) dealers tend to cut stones deep to save the rough stones, therefore, avoid a diamond that has a big depth. A diamond that has a big table is also 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 the Cut of a diamond because the whole body of a stone is affected by it, not a 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.

Tip: We recommend D,E,F, and G as excellent color ranges. H and I diamonds are excellent budget options with J being our lowest recommendation unless some yellowish tint is preferred in a diamond. 

Factor 5: Diamond Clarity

The clarity of a diamond is important because it directly affects its brilliance. If a diamond is full of inclusions, the stone won't sparkle and will lack luster, fire, and scintillation.

The diamond industry has developed a sophisticated system for grading the clarity of a diamond, ranging from Flawless (FL) as the highest grade and Included 3 (I3) as the lowest grade.

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 at the lower end of high quality diamonds and are often considered to be close to being eye-clean in under 1 carat diamonds. Included 1 (I1) and Included 3 (I3) are the lowest clarity graded diamonds.

Tip: FL, IF, VVS/VS1 are excellent premium-grade diamonds. VS2 is a good option to consider while keeping both quality and budget as a priority. SI1/SI2 need extensive due diligence in above 1 carat diamonds to avoid inclusions that affect the brilliance of a diamond.

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 as the other ranges.

According to a GIA study, the appearance of around 10% diamonds was negatively affected among all diamonds that emitted fluorescence. Fluorescence can negatively influence the price of a diamond by up to 25%.

In summary, it is important to note that fluorescence can be a helpful factor to buyers on a tight budget. It can make H or above color diamonds look whiter because fluorescence is often blue which is a complementary color to yellow.

Tip: Fluorescence can be often a plus in H and lower color grade diamonds. However, in higher color grades such as D to G color, no fluorescence is always much better. If you go with fluorescence in D-G colors, make sure you have a valid return policy in case the diamond is among the 10% percent stones that are badly affected by fluorescence.

Factor 7: Diamond Certification

While it is commonly referred to as "diamond certification," within the diamond industry, we refer to the "certificates" as grading reports. Among the many labs that offer grading services, the best lab is GIA (the Gemological Institute of America), a non-profit organization dedicated to educating customers about diamonds and other gemstones. AGS (American Gem Society) also has great a labs for grading diamonds.

Tip: Our top lab is GIA because it is the most consistent grading lab in the world. To avoid getting riffed off, we strongly encourage shoppers to always buy a diamond that is graded by GIA or AGS. If a dealer offers a good deal on a stone that is graded by a bogus lab or not graded at all, there is a strong reason to be concerned. 

What is the Most Important C and What to Prioritize While Buying a GIA Certified Diamond?

A balanced approach to buying diamonds is recommended which means prioritizing the best of all four Cs and fluorescence in a diamond within a given budget range. While carat weight is important, the quality of the cut should always be prioritized. Color and clarity are also important factors.

A balanced approach implies that instead buying a 3 carat SI2, J color diamond, it might be better to buy a well-cut 2 carat diamond with a better clarity and color grade. 

Here are four scenarios to consider 1) buy a diamond in the investment grade range that is very high in all four Cs; 2) buy a diamond that is high quality, but also big. For example, excellent cut GIA graded round diamonds in the 2 carat range, E-G color, VVS/VS clarity, and no fluorescence hold amazing value if bought at the right price; 3) buy a budget option that is still eye-clean such as a diamond with H/I color and SI1 clarity; and 4) compromise on color and buy a big diamond with high clarity and a great cut.

In short, there is no one-size-fits-all approach that can be applied to diamonds because they are wonders of nature, each one unique with its own characteristics. 

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. Diamond prices are also slowly becoming standardized similar to gold prices.

 How the Internet & GIA has 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.

How? Because online competition and the standardization of the diamond grading system have brought transparency into the industry. In addition, before there was no universal standard for grading diamonds and now the industry has established a universal language and grading system for grading diamonds.

Prior to these developments, buyers were at the mercy of local dealers for both price and quality verification. However, now buyers can easily review diamond prices on three to four websites to determine a competitive price range. For example, a buyer can easily establish 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 a stone is graded or "certified" by GIA (the Gemological Institute of America), there is no reason to be concerned if the stone is actually what it should be because GIA is one of the most consistent grading lab in the world.

Diamond Prices Chart:

Petra Gems regularly analyzes the prices of diamonds and provides a comprehensive average estimation of diamond prices in our index. These prices fluctuate on monthly basis, and as soon as significant fluctuation is observed, we update our index.

A host of factors affect diamond prices, including market demand and supply. The availability and supply of rough diamonds which is controlled by large diamond companies, like De Beers and Alrosa, are also primary factors.


We have discussed the necessary factors that diamond buyers should consider while buying GIA certified diamonds. As a result of this article, it should be easier for shoppers to select a diamond with right price and quality within a given budget range. Finally, buyers should prioritize diamonds that are certified or graded by well-known labs.