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Valuation Process

At GemLab Australia, we believe it is important to explain the valuation process we undertake so a quick breakdown of the process is here.

When we assess a gemstone or diamond, we firstly look at the four “C’s” Cut, Carat, Clarity & Colour, as well as origin (Where the gemstone/diamond has come from in the world), and lastly our local market, now to explain further.

Take a treated Pink diamond for example, because GemLab Australia believe ever client wishing to have a Natural Pink diamond

  • Have the gemstone outsourced tested or tested inhouse to confirm type of Gemstone.

  • Cut: is not clarity, the assessment of the cut is purely the outside of the gemstone/diamond, the polish, symmetry, fluorescence and any surface chips, cracks, grazing etc.

  • Carat: this is quite self-explanatory, the bigger and better the gemstone/diamond is the higher the price is, prices are always worked out on a “per carat” for example if a gemstone was $10,000per carat then a 0.50ct (1/2 carat) value would be $5000.00.

  • Clarity is the internal assessment of the gemstone/diamond, these things are Clouds, feather, cracks, crystal, needles, fluids etc this effects the brilliance of your gemstone.

  •  Colour is also worked out on what has already been set on an international market at the “most desired colour” for each gemstone type.  Price per carat can change by thousands of dollars in one change of colour.

  • Origin:  When it comes to gemstones sometimes where the gemstone has come from dictates the gemstones value for example.

    • Emerald per carat is traditionally the most valued of Emerald therefore the price per carat is extraordinarily higher than those from other places such as Zambia, of the same cut, clarity, carat and colour.

    • The Burmese ruby is also the most valued Ruby on the Planet.

  • Local Market: GemLab Australia uses IGS International pricing schedule in US Dollars converted to Australian dollars for most gemstones, however quite often we come across gemstones/diamonds that don’t list on the pricing schedule or our local market dictates the prices also.


The breakdown: i.e., pink diamond

  • Check for the for “C’s”

  • Search the local market for the exact same Cut, clarity, Carat, and colour we can, or as close we possibly can, we try to find a minimum of 6 different diamonds as close to the same parameters as we can, and with a bit of luck from 6 different retailers.

       We take an average of those findings which sets the “Per carat” market price which we then           use for our valuations.

  • After we have a “per carat” price we then look at treatments, for example: for a HPHT or irradiated treated diamonds we subtract up to 60% off the “per carat” price, this is variable depending on how the treatment has changed &/or effected the gemstone/diamond ie. If the treatment is a permanent treatment, if it has caused a foggy look through the gem etc. 

  • We look for certification as this can varies the price per carat significantly up to 60% more per carat when the item is "certified".

  • Shape some shapes the gemstones/Diamonds are cut in dictate a higher price per carat; this can be up to 40% price change per carat.


Most people valuing are going off a pricing schedule that is outdated by up to a few years old, our markets change quite quickly and GemLab Australia believe we have a need to keep up with changes as they occur not in a year or two time. Hence, we do at random new valuation averages for each gemstone &/or diamond as needed, the things that trigger these averages are market impact for example;

Oct 2022, A pink diamond was sold for $49.9 million US dollars in Hong Kong, setting a world record for the highest price per carat for a diamond sold at auction. It was originally estimated to sell for $21 million at Auction, I’m sure you can see how the markets change almost overnight. Now one would think this diamond has come from Australia but in fact Australia isn’t the only pink diamond supplier the diamond was discovered at Williamson mine in Tanzania.


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