Can water cut a diamond? This question often sparks curiosity, given water’s gentle nature and diamond’s extreme hardness. Ordinary water cannot cut a diamond, but the full answer involves understanding the unique properties of both materials and specialized industrial processes.
Diamond’s Unyielding Structure
Diamond’s exceptional hardness stems from its atomic arrangement and strong bonds between carbon atoms. Each carbon atom forms four robust covalent bonds with neighbors, creating a dense, three-dimensional tetrahedral lattice. This stable network makes diamond incredibly resistant to scratching and deformation. Its unique structure is why diamond is recognized as the hardest known natural material, ranking a perfect 10 on the Mohs Hardness Scale.
The Limits of Liquid Water
Ordinary liquid water lacks the properties to cut through a diamond. Water has low viscosity, flowing easily with minimal resistance to changes in shape. It consists of individual molecules not rigidly connected to exert the concentrated force needed to fracture a diamond’s strong covalent bonds. Water at typical pressures cannot apply enough localized stress or possess the abrasive qualities required to overcome diamond’s inherent durability.
Water’s Role in Abrasive Cutting
Waterjet Technology
While pure water cannot cut diamond, water plays a role in advanced industrial processes like abrasive waterjet cutting. This method uses water pressurized to extremely high levels, typically ranging from 60,000 to 94,000 pounds per square inch (PSI). This ultra-high pressure converts into supersonic velocity as water exits a tiny nozzle, often reaching speeds up to three to four times the speed of sound.
Abrasive Action
To cut hard materials, abrasive particles such as garnet, aluminum oxide, or silicon carbide are introduced into this high-velocity water stream. The combination of immense pressure, high velocity, and the abrasive particles enables the cutting of very tough materials. The abrasive particles, propelled at high speeds by the water, physically erode the material through chipping and fracturing upon impact. While some sources indicate that abrasive waterjets can cut diamonds, challenges such as nozzle wear and material waste can arise, and the process may be slower for diamonds compared to softer materials. This “cold cutting” process avoids heat-induced damage, which can be beneficial for sensitive materials.
How Diamonds Are Truly Cut
Diamond-on-Diamond Cutting
In industrial settings, diamonds are cut and shaped using methods that exploit their unique properties. The most common technique involves using other diamonds as the cutting tool. Diamond-coated saws, wheels, or diamond dust embedded in a bonding material grind and shape the rough stone. This is effective because only a material of equal or greater hardness can effectively abrade a diamond. Traditional methods sometimes involve cleaving, where a diamond is split along a plane of weakness using a sharp blow after a groove is made by another diamond.
Laser Cutting
Modern advancements include laser cutting, which uses highly focused light energy to process diamonds. Lasers, such as Nd:YAG lasers, concentrate energy to a tiny spot on the diamond’s surface, converting carbon into graphite through extreme heat, which then vaporizes. This method offers precision and can cut intricate shapes, although it can be a lengthy process and may leave slight discoloration due to the graphite conversion.