The process of cutting and polishing gems is called lapidary. All gems are cut and polished by progressive abrasion using finer and finer grit.
Diamond, the hardest naturally occurring substance, is used to cut and polish the hardest stones.
The rough material is cubed, slightly larger than the required finished bead size, before being inserting into the Bead Mill.
Bead mills are used to grind and sand large quantities of beads simultaneously. They typically employ a grooved lap and a flat lap between which the beads are rolled and worn to shape.
Silicon Carbide grits are used to shape the rough into round shapes. Different types of material require different grits, milling times, etc.
After shaping and sanding, beads are usually drilled and then polished by tumbling. Tumbling is turning large quantities of beads at a slow speed in a rotating barrel with abrasives and water for extended periods (days or weeks).
By tumbling with progressively finer grades of abrasive (usually silicon carbide) and washing carefully between grades, the beads are gradually smoothed and polished. Tumbling barrels are often hexagonal in outline in order to enhance the stirring action of barrel rotation. An alternative to rotary tumblers is a vibratory machine, often called a vibratory tumbler, in which the containing barrel vibrates rather than rotates.
The more stationary arrangement of vibratory machines makes it much easier to examine the progress of the stones inside, whereas standard tumblers must be halted in order to check progress.
Today, most semi precious gemstone beads are cut in standard round sizes – ie 4mm, 6mm. 8mm, 10mm etc. Often there is a .5mm +/- tolerance in the finished size. They are usually sold as 15” or 16” loose strung strands.
Semi precious beads are a natural material and therefore some natural inclusions, variations in colour and patterning are normal. This is what makes them so exciting and why jewellery designers love to work with them.