Opal Cutting & Polishing - How to Cut and Polish an Opal

A beautiful opal ring setting or necklace is preceded by a lot of time and effort invested in the gemstone. The process involves individuals who specialize in niche skills.

Preliminary Stages

The first step to jewelry grade opal creation is to buy raw opals directly from opal mining companies. These are rough rocks and untouched, except in the course of the mining process. The buyers at this stage are the gemstone artisans. The trade name of unfinished opal is “parcel” and parcels are large quantities of the gemstone in their most durable and roughest states.

Potential buyers of opal gemstones sort through parcels and try to predict the stone values which will be ultimately produced from the rough material. This calculation is not easy as the skill of cutting and polishing the opal stone is an extremely specialized one. What complicates the process even more is that with each progressive cutting, the malleability of the opal stones decreases.

Intermediate Stages

After the opal cutter has decided on his hoard, a diamond saw is utilized to cut rough opal into the “rubs”. The end of the slicing process would result in the opal being cut into the fundamental stone shape.

At this stage the opal stone roughly resembles the image of the finished stone as imagined by the cutter, who attempts to minimize waste and maximize the size of the precious stone. This is carefully done as each cutting reduces the stone size. Clean and warm water is used during the opal cutting process to avoid any overheating caused by friction. The stone can be “burned” or cracked if exposed to extreme temperatures. Undesirable, small pits are formed when a stone is burned.

After the saw cutting process, the opal stone is placed on “dop sticks” made out of lengths of wood doweling or nails. Heated wax is then used to adhere the opal to the tip of the stick; this allows greater control. The opal cutter decides on the face of a particular stone, which is dependent on the best shape and color that can be brought out.

Finishing

The opal cutter then uses diamond grinding wheels to shape and perfect the opal. It is important to eradicate imperfections on the stone like saw marks and sand spots. The stone face is made to be cabochon-shaped (a dome shape) and the final shape depends on the quality of the stone. The stone size must be kept as big as possible throughout the process.

The last stage sees the stone being polished. Some traditional cutters use cerium or tin oxide whereas many newer cutters use extremely fine diamond powder. It imparts a stunning sheen to the opal. The gemstone is now an alluring and spectacular investment.