Custom Cut Gemstones and Diamonds

One of my favourite things within my role of being a jewellery designer is having the opportunity to look closely at a large number of loose gemstones. Life as a bespoke jewellery designer involves finding out what cut of gemstone a customer wishes to include and watching this selection lead on to a truly personal design. Also, fantastic when we have a slightly different shaped gemstone in stock that a customer falls in love with, which helps create a design that is equally as unique! What is truly fascinating is the large number of shapes in which a gemstone can be cut.

Gemstone cutting (also known as lapidary) is the process where a rough stone is turned into a gemstone. If done correctly, the very skilled task of a gemstone cutter is to ensure once cut a gem is –

a) even colour in colour
b) contains an acceptable number of inclusions
c) has good brilliance
d) showing the majority of its carat weight when viewed from the top

The main steps involved when cutting facetted gemstones are:

• Step One – Slicing

Also called sawing, slicing is one of the most crucial stages in the finishing of gemstones (if not the most crucial), as it will ultimately determine the size and beauty of the finished gem. Once the rough is selected, using a diamond-tipped circular steel saw, the gem slicer will determine how to cut, where to cut, and how many pieces to cut, in order to produce the highest quality. If the rough is cut incorrectly its potential beauty may be lost.

• Step Two – Pre-forming

Once the rough has been carefully sawn, pre-forming commences. This process requires lots of experience and concentration. Pre-formers carry a great responsibility, as they determine both shape and orientation for each gemstone; mistakes at this stage can be very costly. Apart from the appearance of the finished gem, pre-formers always bear in mind the weight of the finished gem. Pre-forming is typically performed by using a vertical steel grinding wheel.

• Step Three – Shaping

The shaper uses a special type of heat activated resin to affix the pre-formed gemstone onto a metal rod, often referred to as a dop stick. The shaper then delicately applies the gemstone to the shaping wheel to obtain a more accurate presentation of the facets and size. Due to the level of precision required in the shaping process, a shaper is usually a very experienced pre-former. Shaping is completed using a hand-operated shaping wheel.

• Step Four – Polishing

The final step is known as polishing. Once gemstones have reached their ideal size and shape, they are taken to a steel horizontal polishing wheel where the polisher completes the faceting and gives them a final polish using fine diamond paste to reveal their inner lustre, brilliance and fire.

Each cut gemstone is a true piece of art – no matter how large or small. So why not consider this for your own bespoke engagement ring.