Diamonds are known for their sparkle and shimmer. Their ability to catch your attention across a room is practically unrivaled by other jewelry. But these precious gems weren’t always so perfect, shiny or glamourous. Before finding their way into necklaces, earrings, bracelets, rings and more, diamonds were pulled from the earth’s crust as dull, lackluster stones. A diamond’s true beauty and fire aren’t exposed to the human eye until it's cut and polished. This process is intricate, and precision is critical. Read on to see what it takes to turn rock into glam.
How Are Diamonds Cut?
Have you ever heard of a lapidary, or lapidarist? A lapidarist is a person who practices the art of cutting, polishing and engraving precious stones. It takes a skilled craftsperson to transform rough diamonds into the dazzling gems we know and love. This cutting involves meticulously analyzing the diamond’s internal structure and strategically removing facets (one of the many sides of diamonds) to maximize the diamond’s fire, brilliance and scintillation, which refers to the colorful light show that occurs when a diamond moves in various directions. In essence, the cut of a diamond is the magic that unlocks its hidden beauty.
The Diamond Cutting Process: Five Master Cuts to Brilliance
Getting a proper understanding of this detailed diamond-cutting process requires a closer look into each of these five intricate steps.
1. Planning
The planning stage is where the diamond's potential is discovered. Cutters use advanced software to map out the ideal cut to maximize sparkle, weight, and overall beauty.
2. Cleaving or sawing
Next, the rough diamond needs shaping. Cleaving uses the diamond's natural grain to precisely split it, while sawing (with a diamond blade or laser) tackles more challenging sections. Even the slightest mistake during this step can negatively impact a diamond’s beauty and value.
3. Bruting
Two diamonds are secured to spinning axles turning in opposite directions during the bruting process. The two diamonds grind against each other, shaping each into a more rounded shape. This process is sometimes also called girdling.
4. Polishing
This is where the magic really happens. Once the rounded diamond shape is formed, the diamond facets (flat, polished surfaces) must be created. The number of diamond facets will depend on the diamond’s original structure and the desired diamond cut. Two key phases exist within the polishing stage:
a. Blocking
Blocking is the initial shaping stage. A skilled craftsperson presses the diamond against a spinning wheel which revolves 3,000 times per minute. Spinning at this rate grinds the stone into its basic form, creating four main facets:
- Crown: The top part of the diamond, above the girdle (the widest area).
- Pavilion: The lower part, beneath the girdle, ending at the culet (see below).
- Table: The flat, topmost facet of the crown.
- Culet: The tiny facet at the very bottom of the pavilion, which can be pointed or rounded. This phase focuses on maximizing the diamond’s weight and establishing the overall diamond shape while setting the angles for optimal light reflection.
b. Brillianteering
During the brillianteering process, the crown and pavilion’s minor facets are added and adjusted to maximize the diamond’s light return and beauty.
5. Inspecting
The final step involves a keen eye. The polished diamond is examined under high magnification to ensure flawless finish, symmetry and adherence to the original cutting plan.
There's a constant battle between maximizing a diamond's brilliance and minimizing wasted material for lapidarists. Early cutting techniques prioritized preserving as much of the rough diamond as possible, resulting in less sparkly gems. The modern round brilliant cut, known for its fire and brilliance, sacrifices some of the rough diamond in exchange for a more dazzling finished jewel.
Tools Used in the Diamond Cutting Process: What Can Cut a Diamond?
You’ve likely figured out this diamond-cutting business isn’t done with a sharp knife or scissors. It is said that a diamond can only be cut by another diamond; however, weaknesses within a diamond's structure can be exposed using special tools. The following tools combine cutting, grinding and spinning to give a diamond its finished look.
- Cleaving knives/saws: This specialized knife or saw, often with a diamond-coated blade, is used to make the first cut in the rough diamond. To minimize waste, jewelers split the gem along its natural grain lines.
- Bruting machine: Traditionally done by hand, this machine uses two rotating axles with diamonds attached, grinding together as they spin in opposite directions to form a rounded diamond. Modern bruting machines are computer-controlled for maximum precision.
- Lasers: Lasers have become increasingly important tools in diamond cutting. They can be used to cleave very thin or “included” diamonds (those with microscopic flaws) and to inscribe microscopic identification marks on the finished gem.
- Diamond polishing wheel: After the diamond is bruted into a round shape, it is polished on a wheel, typically containing a diamond powder, to achieve its final brilliance and shine.
In addition to these tools, diamond cutters also use a variety of other equipment, including microscopes, loupes and calipers, to examine and measure the diamonds.
How Long Does It Take to Cut a Diamond?
If you’re simply looking at the time it takes from planning through final inspection, a professional diamond cutter takes about two weeks to finish a diamond cut. If you include the time it takes for a diamond to form, be discovered and ultimately cut and polished, this process takes anywhere between one and 3.3 billion years (and two weeks, to be precise!).
Each diamond is unique and requires a custom approach. A diamond with a complex structure may require a lengthier planning period or a slower shaping process; therefore, the duration between raw diamond and sparkling gem will vary from one stone to the next.
Can You Reshape a Diamond?
Yes, professional diamond cutters can reshape a diamond. Sometimes, people become owners of a diamond they love via gift, inheritance or something else, but they aren’t in love with the cut and may want to reshape it. However, it is a gamble that some professionals warn against taking because reshaping the stone requires additional cutting, which can result in losing a large portion of the original diamond (i.e., waste). These professionals suggest you consider a new setting for your diamond rather than reshaping it.
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