Cut and Carat

Table of Contents

CUT

At Aussie Sapphire we only use the best cutters who have years of experience with our stone and we pay them accordingly.  While it is possible to get cutting done very cheaply, often the results are disappointing. Most larger gem merchants will select the best gems for our best cutters - included or lower grades will be cut more cheaply but still the very best we can. Aussie Sapphire is very proud of our Australian contract cutters and our factory in Thailand where workers are paid above the average wage.  It is possible to find stones cut cheaper in Thailand but we have never supported this kind of exploitation - all workers should have the opportunity to use their skills to improve their lives and develop their trade. 

Many very cheap gems suffer from poor quality cutting (see examples below) - gems with a better quality cut will be immediately obvious and represent far better value.

Unlike diamonds, coloured gemstones are not graded for “ideal” cut as each different type of gem reacts differently to how light passes through the stone.  For best results, the facets need to be uniform, well polished and cut at the correct angles to maximise light return.  Cut is described as shape with all dimensions expressed in millimetres.

For sapphires and other coloured gemstones, Cut quality may be assessed in terms of Proportion (symmetry and geometry of gem face & profile) and Finish (polish and quality of faceting).  The look of the finished gem depends on the skill of the cutter in bringing the gem to life.  You should look for gems that are well balanced with facet angles meeting correctly and a well polished finish on all parts of the gemstone.  Common problems include obvious flaws in polishing, surface chips (sometimes called "naturals" by sellers who do not wish to reduce the weight by removing these flaws), unpolished girdles (commonly found in very cheap gems), unbalanced proportions. 

Cutting for weight - this can be a problem where gems are not cut to the correct angles but for maximum weight retention.  These gems will often be less attractive than those cut using precision methods. However, the other issue is that you may be overpaying for carat weight - for example, a stone with a very deep "belly" will have a smaller face-up size than the weight would indicate and may be difficult to set in a standard setting (custom work by a manufacturing jeweller is more expensive).

When buying from Aussie Sapphire, you may be certain that all of our stones are cut suitable for the quality and price range of the Gem.

CARAT

Gemstones are weighed in carats.  One carat is equivalent to 0.2 gram (ie. 5 carats = 1 gram).  As many gems are traded on a $/carat basis, you will find that we often quote a per carat price for your guidance.

Obviously a gemstone of larger carat weight will be more valuable than a smaller one.  However, this rise in price is not always linear.  Where gemstones are commonly found in large size, the price per carat may not vary greatly across the range of sizes commonly sold.  However, for stones which are very rare in large size (such as sapphire), there is often a stepwise increase in per carat price as the gems increase in size. In these cases, a premium is paid for the larger and more rare gems – the small gems may be still quite affordable but the price rises significantly for larger sizes.  This issue is discussed in more detail in the Supply & Demand page.

Sapphires have a higher specific gravity than diamond (ie. they are more dense) so a sapphire cut to the same dimensions as a diamond will weigh slightly heavier. Conversely, a sapphire weighing the same as a diamond will be slightly smaller in dimension. When ordering gemstones to fit an existing setting, we recommend that you quote the required dimensions rather than carat weight as weight varies between different types of gems and according to type (depth) of cut.

As a quick guide, the largest price jump occurs at 1ct and above, then 3ct and above, then 5ct.  Dealers will have different systems of pricing but generally, the rare gems such as sapphire show incremental rises in per carat price. 

Go back to the Grading and Pricing page.
Go to the next section - Supply & Demand