Where are Diamonds Mined?
Diamonds are primarily mined from kimberlite and lamproite pipes. These are volcanic formations that bring diamonds from deep within the Earth’s mantle to the surface. When a diamond-bearing pipe is located, large-scale mining operations use heavy machinery and advanced technology to extract the diamond-rich rock.
In addition to primary sources, diamonds are also found in alluvial deposits. These occur where rivers and erosion transport diamonds away from their original volcanic source and deposit them in gravel beds. These alluvial deposits can often be mined using simpler methods, sometimes even by artisanal miners.
Historically, India was the first known source of diamonds, mainly from alluvial deposits. In the late 19th century, significant discoveries occurred in South Africa near Kimberley. This led to the rise of large mines and companies like De Beers, which once controlled a substantial share of global diamond production.
Today, the world’s leading diamond producers include Russia, Botswana, Canada, Australia, and several African countries like Angola and South Africa. Russia’s mines in the Yakutia region, such as Udachny and Mir, are among the largest. Botswana’s Orapa and Jwaneng mines are also top producers. Canada’s Ekati and Gahcho Kué mines add to significant global output, and Australia’s Argyle mine was well known for its pink diamonds before its recent closure.
Diamonds have been found in numerous countries worldwide, including the United States (notably Arkansas), but commercial mining is mainly active in a handful of countries with economically viable deposits.
How are Diamonds Cut?
Mapping the Rough
Cutters begin by studying the rough stone under magnification and with 3D imaging software. They model internal inclusions, crystal orientation, and extreme variations in clarity to select a shape that maximizes carat weight while enhancing light return. For lab-grown diamonds, which share the same crystal structure as stones formed deep in the mantle under high pressure and high temperature, the planning step looks identical and uses the same scans and algorithms to predict yield.
Splitting and Sawing
Natural diamonds often have cleavage planes, lines along which the crystal will split cleanly. Cutters use these planes to cleave a stone with a precise blow or to orient a saw. When no safe cleavage plane exists, they use a diamond-tipped saw or a laser to cut through the lattice. Lasers vaporize material with minimal vibration, which helps when an inclusion sits near the intended split.
Bruting
Bruting gives the stone its basic outline. For a round brilliant, the cutter grinds two diamonds against each other on a spinning lathe to create a true round girdle. For fancy shapes—oval, emerald, cushion—bruting uses abrasive wheels and controlled motion to build the desired silhouette while keeping symmetry and maximum carat retention.
Pre-forming with Lasers and Computer Guides
Before final facets are laid down, cutters often pre-form the stone with laser sawing and automated grinding. Laser pre-forming can remove a section around a stubborn inclusion or create fine cuts for fancy shapes. Computer-assisted design and machine control let cutters index facets precisely so the final stage starts from a stable, predictable blank.
Polishing Facets
Polishing transforms planes into precise facets that reflect and refract light. Cutters mount the stone on a dop stick, set it against a rotating scaife charged with diamond powder, and polish each facet according to exact angles. The angle and placement of each table, kite, and star facet determine how light refracts through the crystal lattice and returns to the eye as sparkle and fire.
Proportions and Optical Performance
A stone’s crown height, pavilion depth, and table size control light performance. If the pavilion is too deep, light leaks out the sides. If the table is too large, you lose dispersion. Tools that simulate light paths let cutters aim for optical targets that maximize brilliance, scintillation, and color performance in the stone.
Symmetry, Polish, and Visual Grading
After polishing, cutters inspect the symmetry of facet alignment and the quality of each polished surface. Tiny polishing lines or off-axis facets reduce performance and lower grade. Labs assess these attributes alongside clarity and color to produce a report that tells how the cut will present to the observer.
Modern Tools
Computer-assisted design and robotic polishing speed repeatable cuts and reduce waste. Robots can index a stone to within tiny tolerances and apply consistent pressure during polishing. Laser etching marks a stone with ID numbers and can also remove inclusions selectively before traditional polishing. These tools complement hand skills rather than replace them.
Specialty Cuts and Custom Work
Fancy cuts like the emerald, asscher, and heart require different polishing sequences and a higher degree of human judgment. Cutters balance optical goals against the crystal’s natural growth direction and any internal features. Clients can request custom proportions to emphasize color or size, which changes how facets are arranged and how light behaves inside the diamond.
How are Diamonds Priced?
Diamonds are priced primarily based on the well-known 4Cs (Cut, Color, Clarity, and Carat weight). These four characteristics combine to determine a diamond’s quality and market value.
Carat measures the diamond’s weight, with one carat equaling 0.2 grams. Larger diamonds become exponentially more expensive because bigger stones are much rarer than smaller ones. For example, a 2-carat diamond can cost more than twice as much as a 1-carat diamond of similar quality due to its scarcity. Slight differences in carat weight around pricing thresholds can also cause significant price jumps.
Cut quality affects how well a diamond reflects light, influencing its sparkle and brilliance. A superior cut grade generally commands a higher price because it enhances the diamond’s overall beauty, regardless of size.
Color is graded on a scale from D (colorless) to Z (light yellow or brown tint). Diamonds closer to colorless tend to be more valuable. However, near-colorless grades like G or H offer a good balance of appearance and value, appearing nearly white but costing less than the highest color grades.
Clarity assesses how free a diamond is from internal flaws or blemishes. While flawless diamonds are exceedingly rare and costly, most inclusions are microscopic and have minimal effect on beauty, allowing buyers to save by opting for slightly lower clarity grades.
Besides the 4Cs, diamonds with fancy colors such as pink, blue, green, or yellow are valued differently. These fancy colored diamonds are much rarer and can be extremely expensive due to their unique hues and scarcity.
Buying a diamond is an exceptional experience. When you visit us at PriceScope, we’ll talk about what’s most important to you (size, sparkle, or budget), and walk you through each diamond’s qualities so you feel confident and informed.
