The Ultimate Guide to Buying Raw Diamonds

Fused deep in the earth’s crust under immense pressures, the beauty and mystery of raw diamonds have fascinated people across many widely differing cultures through the ages. Also called rough diamonds, raw diamonds can look similar to quartz before they are cut and polished, making appraisal difficult even for the trained eye. However, they can offer a unique opportunity for those willing to do the work. 

Understanding Raw Diamonds

Raw diamonds, or rough diamonds, are diamonds as they are found in their natural state. They can look a lot different than finished diamonds, making it hard to assess their final brilliance and value without doing many different kinds of tests.

When testing raw diamonds, experts use a standardized set of parameters when making their assessment. They come in many different colors, shapes, and sizes, with varying amounts of flaws and levels of clarity. Each of these properties can greatly affect the gemstone’s final value, depending on their rarity and combination. 

Raw diamonds often look like a simple piece of glass or shard of quartz to the untrained eye. Although valued in themselves in their untouched, natural state, most people are used to seeing diamonds only in their finished form, making the look of raw diamonds a bit surprising. Once a person has handled and examined many hundreds of them, though, there are many characteristics that can be seen and evaluated by experts. 

How are Raw Diamonds Sourced?

Rough diamonds are sourced in two ways: pipe mining and alluvial mining. 

1. Pipe mining: The more standard form of diamond mining, it involves extracting diamonds from “pipes” – volcanic fissures – near the earth’s surface. 
2. Alluvial mining: While almost all natural diamonds are formed in volcanic fissures, Some of these are carried by erosion into riverbeds and beaches. Alluvial mining focuses on these transported diamonds.

Why Choose Raw Diamonds?

There are two main reasons people buy raw diamonds:

1. Investment Potential: Raw diamonds can appreciate in value, especially if they are rare or have desirable qualities. This is a very common reason people buy raw diamonds, in the hopes that their assessment of them will yield a better value in the final diamonds than the cost of the labor and the raw diamond itself.
2. Customization: Buying a raw diamond allows you to customize the final form of the finished diamond, allowing you to create a truly unique piece of jewelry. This is a great use of raw diamonds, as you may be able to find unexpected uses of oddly shaped ones.

Evaluating Raw Diamonds

First-time buyers of raw diamonds can often mistake them for other minerals like quartz, which can appear identical to uncut diamonds. Identifying genuine raw diamonds typically requires a series of rigorous tests, including their hardness on the Mohs scale, internal components, refractive index, and their origin.

The following are the main factors that affect a diamond’s value:

1. Carat Weight: The weight of gemstones in carats. Larger stones are typically more valuable, although this also depends on the other factors on this list.
2. Color: Raw diamonds come in a wide spectrum of colors. While clear diamonds are traditionally the most highly valued, there are some colored diamonds that fetch equally high or even higher prices.
3. Clarity: This refers to the internal and external flaws of a diamond. In raw diamonds, clarity can vary greatly and is the most important factor affecting the stone's value after weight.
4. Shape: Each raw diamond’s natural shape defines how it is best cut and, for that reason, a good amount of its value. Some shapes are more desirable than others, depending on current market trends. 
5. Sawn: A 'makeable' stone can be cut such that you can get one polished diamond from it. 'Sawable' diamonds can be cut in half to create two or more diamonds with better shape. 

You can look up online calculators that can estimate the typical amount of weight that will be lost from raw diamonds after being cut and polished, giving you a good estimate of their final value. Rough shape, inclusions, crystallizations, deformations, and internal stress can all play a role in this calculation.

Using a 1-carat raw diamond as a guide, here are the standard expectations of weight loss after being cut and polished:

In addition, you should look for conflict-free diamonds that comply with the Kimberley Process Certification Scheme, which helps to prevent the sale of "blood diamonds." Most reputable dealers will be able to provide this as the issue has gained a lot of traction and has been greatly eased in the last decade.

After being processed, you can get the diamond evaluated at one of the numerous diamond grading laboratories. Two of the most used of these are the Gemological Institute of America (GIA) and the American Gem Society Laboratories (AGSL). At these facilities, the diamond's color, clarity, carat weight, and cut quality are meticulously examined and evaluated.

Diamond Polishing Process

Whether you’re looking to turn your raw diamonds into polished stones for a handmade piece or you’re just looking to invest in the best rough diamonds for others to cut and polish, it’s essential to know how the process works.

Transforming a rough diamond into a polished gem involves five (5) phases:

1. Planning: During this initial phase, the final diamond's size, clarity, and shape are precisely planned to avoid any costly mistakes. 
2. Sawing: Some raw diamonds may be cut to make multiple smaller diamonds if the shape makes more sense when cut in two or more pieces to get a desirable final form.
3. Bruiting: During bruiting, the diamond is spun against another diamond to shape it, forming a rough outline of the final shape before moving on to more precise polishing. 
4. Polishing: Consisting of blocking (polishing initial facets) and faceting (creating the final facets), to achieve the diamond's full brilliance. 
5. Inspection: A final examination of the diamond’s cleanliness and adherence to quality standards. 

The whole process aims to use as much of the raw diamond as possible, given its shape and flaws, to keep the most weight while producing the highest-quality and most brilliant final cut and polish. 

Conclusion

In the end, the only thing left to do is to jump in feet first and start learning through experience. Whether you are looking for raw diamonds for their own sake, for custom jewelry, or as a potential investment, the game has been played for a long time. Similar to the stock market, there are many expert and amateur diamond appraisers out there looking for their edge.

Take your time, get to know the gemstone and the dealers in your area, and maybe, just maybe, you’ll find that edge for yourself.