Crystal engraving is the process of carving an image or text into the surface of an object made of crystal. This can be achieved in several ways. The simplest method involves hand engraving with a tool that has a diamond tip. Another method uses a pen-like device that emits abrasive crystals, glass or sand that can mark a crystal surface evenly. Lasers also can be used for crystal engraving, either with a handheld laser or an automated, computer-controlled industrial version.
The composition of crystal is similar to glass with the exception of the addition of lead that can increase durability and shine. This means many crystal engraving techniques are identical to those used on glass. The original method of engraving crystal is to use hand tools that have hard diamond tips. These tools can be completely manual, like a glass cutter, or they can be electronic, with a tip that spins or moves pneumatically in and out. Hand engraving crystal can yield elaborate and detailed results, although it takes some time to complete and often does not penetrate deeply into the crystal.
The technique known as sandblasting is frequently used in crystal engraving. This process involves creating stencils that are applied to the surface of the object and then using a tool that directs a fine stream of an abrasive material at the surface. The stencil protects areas of the crystal, allowing only the exposed regions to be etched by the abrasive. This can create very intricate work in a relatively short amount of time. The use of a stencil to create the design means sandblasting can be very effective when engraving multiple items with the same pattern.
One of the most recent developments in crystal engraving is the use of lasers. Unlike other tools that precisely carve into the crystal, a laser creates micro-fractures in the crystalline structure, effectively breaking off tiny pieces of the object. Lasers work very quickly and can be automated to exactingly reproduce images and photographs on a crystal surface. Some engravers do not like the results of laser crystal engraving because, if there are wide areas of engraving, the surface that has been treated with the laser tends to be noticeably uneven and sometimes ragged.
Laser crystal engraving has made one unique technique possible, namely engraving the inside of a block of crystal. By using a laser that is emitted in a very wide beam and then focusing that beam to a single point some distance away, the laser is able to penetrate a block of crystal without damaging it. The spot where the laser comes to a point, such as the tip of a cone, is the only spot where the heat is strong enough to create a micro-fracture. This means a three-dimensional image can be carved on the inside of the crystal, leaving the outside surface polished and clean.