BIRON® Rough Stone

Rough gemstones are uncut gems that are made up of crystalline structures and can be cut into desired shapes through faceting or cabbing and polished to reveal their lustre.

A gemstone in the rough is a raw gemstone that has not yet been cut or polished. Rough gemstones can be dull-looking, but can also be shiny with no reflection.

Natural gemstones are found in the rough when mined while synthetic gemstones that are grown in a laboratory are made into a rough form. In both cases, gemstones made or found in the rough offer manufacturers and factories the chance to maximise the surface area for cutting to create the ideal shape, while maintaining carat weight, clarity and colour. Dealers then sell these stones to manufacturers whose jewellery craftsmen would mount the faceted and polished gemstone according to designs by designers and create finished jewellery pieces, which are then supplied to jewellery brands and retailers.

Inter-Pacific provides meticulous cutting and polishing services to BIRON® Rough Stones that maximise light refraction and bring out the colour of the gemstones for the highest quality finish.

Varieties of Beryl: Emerald, Aquamarine, Morganite, Bixbite, and Heliodorl. Photo credit: Jeff Scovil/GEOLOGYIN

In the melt process, the chemical composition remains the same throughout, from start to finish. Methods of this process include flame fusion or the Verneuil method, and the Czochrolaski method more commonly known as the crystal pulling method.

In the solution process, the resulting chemical composition differs from that of the start, but the chemical composition and other properties of the end result are the same as a gemstone’s natural counterpart. Methods of this process include flux melt and hydrothermal growth.

Flame-fusion synthetic sapphire crystals. Photo credit: Hrand Djevahirdjian(left), StoneSunberg(right)

Rough gemstones are cut and polished through gem cutting which is covered by the term lapidary. The process is the same for both lab-grown and natural roughs. This involves a progression of abrasion by grit of harder substances, such as diamond, which holds a hardness level of Mohs 10. This is often used to cut and polish both gemstones and diamonds. Another common compound used is man-made silicon carbide grit of different sizes that holds a Mohs hardness of 9.5. These include sawing, grinding, sanding, polishing, drilling and tumbling.

Using these techniques, gemstones can be shaped into the following forms: cabochons, faceted stones, beads and spheres, inlays, intarsias and mosaics, cameos and intaglios, and sculptures.

A rock saw with a circular blade is used to cut into a rough gemstone. Water and oil are used to wash away debris and avoid overheating the saw blade or stone. The saw blade is usually made up of steel or copper, or a phosphor bronze, which is then impregnated with diamond grit along the outer edge for sawing.

Wheels are used to shape gemstones into a roughly desired shape known as a preform. This is done by using a silicon carbide or diamond-impregnated wheel, whereby oil and water are also applied to prevent overheating. Very coarse diamond or silicon carbide can rapidly remove the non-gem part of the stone, while finer grit is used for final shaping and sanding.

This method is used by a gem cutter to create desired holes into gemstones, such as beads. This is done by using a diamond-tipped rod or tube that rotates into a gemstone.

Is used to smooth and polish larger quantities of rough gemstones, for example, to make beads. A rotating or vibratory tumbler can be used to wash stones with a combination of finer grades of abrasives and water over days or weeks.

Drilling gemstones. Photo credit: GEMCROWD