Ruby: Natural or Synthetic?

A friend sent me a ruby to help assess the value a parcel they were considering as an investment. On first glance it looked like a very nice gem, but all that can be said about it at that stage is “it is a red transparent stone”.  The parcel was reported to have come from the Luc Yen mines in Vietnam, a source of exceptional rubies and spinel.

The first step is to determine if it is actually ruby. A minute or so with the refractometer revealed an RI of 1.762 to 1.77, as expected for corundum. It’s birefringent nature was verified under the polariscope, with a lovely uniaxial figure. No more testing needed here, it’s clearly corundum.

Next is to look under magnification. Under a 10x loupe, the gem is remarkably clean, there are no inclusions to be seen at all. This is either an exceptional natural ruby, in the order of $10,000 per carat, or it is a synthetic worth tens of dollars per carat. One point of note is that the girdle was not polished and many of the crown facets were misaligned. Generally I would expect a top value ruby to also have excellent facets and finish.

fig1: Misaligned facets on the crown

Under higher magnification, 30x, the gem was still essentially flawless. However, under diffuse lighting curved colour banding could be clearly seen.  Curves simply don’t appear in natural corundum, but are a common feature of synthetic gems made with the flame fusion process.

These photos were taken with a Canon DSLR and 100mm macro lens.  The ruby is 6.5mm in circumference and the optics are pushed to their limits to get an image at about 25x magnification.  Nevertheless, the features are clear enough to be made out, though they are much more obvious under a microscope.  The white spots are just specs of dust on the surface.

fig2: Diffused light shows curved colour banding

At this point there is no doubt it is synthetic ruby. A very nice gem, but worth maybe $30 at most.


A Diamond Story

The Request

Some people have a firm idea about the sort of ring they want, others, not so much. It is always nice to be able to find gemstones and design jewelry to match request, but it is just as pleasing to be given the trust to ‘make something beautiful, but I don’t want to spend too much’. So that what the brief – something truly beautiful and unique, for less than 7,500 Euro.

Mission accepted!

Finding the Diamond

It took three weeks, but it was worth it. We considered a number of round brilliants, from VS to VVS1 and G to I colour, all beautiful stones, and any one of them would have looked great in the right setting. And then we found this:

Emerald cut diamond 1.01ct angle view Emerald cut diamond 1.01ct front view

A 1.01 carat emerald cut, F colour, and, amazingly IF – internally flawless. We could hardly believe it, but the certificate doesn’t lie.

Emerald diamond cut IF GIA certificate

There really is something special about an IF stone that separates it from mere VVS1 and VVS2 diamonds. There shouldn’t be, right? VVS1 inclusion can barely be seen at 10x magnification, let alone with the naked eye, let alone from a few feet distance. Yet, when you see this stone, it immediately stands out out something very special. And the more you look at it, the more special it becomes.

Designing the Setting

The next question is what setting would best grace such a gorgeous diamond. A gemstone like this really speaks for itself, it doesn’t need any embellishment. Several designs were considered, and. like us, the customer prefered a simpler setting with an elegant, thin band.

Diamond ring custom design emerald cut

After the wax was made, there were a couple of small adjustments. We reduced the number of side stones by four, and thickened the width slightly for better durability.

The Result

And this is how it turned out:

Yes, we said ‘wow’ too.

Did we succeed?  Let’s see:

  • Beautiful – customer says a resounding “YES!”
  • Unique – A very rare IF emerald cut diamond in a one-off designed ring, that is also a “yes”
  • Less than €7,500 – after shipping and insurance, there was change of €130.

Most importantly though, the customer absolutely loved it.  A very satisfying result.

Mission accomplished!

Gold Sheen Sapphire Price Update April 2018

This update for Gold Sheen Sapphire pricing uses sales price point data from Tucson, Hong Kong and Bangkok exhibitions, as well as shop front sales from January to April 2018.

Gold Sheen Sapphire Price History 1st Half 2018

Prices have increased for all grades, most notably for grade 1 and 2. Increased pricing was a result of strong interest from Japanese buyers, which flowed over to grade 2 pricing as well. Grade three pricing was a more general result of broad buyer interest.  Most notably highest quality pieces reached $1,000 per carat – a significant milestone for Gold Sheen Sapphire.

If you would like information about how to invest in Gold Sheen Sapphire you can visit our wholesale page: or email


Exquisite Sapphire Ring

Making beautiful jewelry from top grade gemstones is always a great pleasure.  We recently had a long time customer request for a sapphire ring from a stone that had previously been set in a pendant.

Sapphire Pendant 3.5ct
Original sapphire in pendant.

This is a 3.54ct Ceylon sapphire that I bought in Sri Lanka a few years ago.  The customer requested if it could be made into a ring.  Originally it was set with white sapphire, but the customer request was to use diamond.

After a couple of design drafts, this is the design that was settled on, option ‘B’:

Sapphire ring design options.
Sapphire ring design options.


Consequently, this was the finished product:

Absolutely gorgeous.

And from the customer: “It is a perfect fit and I am the envy of the office. It is absolutely beautiful. Thank you!!”

Thank you Yin, thrilled that you love it and it was a pleasure to make it for you.

FIG Recognises Gold Sheen Sapphire

The Federated International GemLab SA in association with the International Colored Gemstone Association now recognises Gold Sheen Sapphire as a unique variety of corundum.

Six certificates were issued by the FIG Bangkok office on 20th November.

Gold Sheen Sapphire Certificate
Gold Sheen Sapphire FIG Certificate No. 2114612414
Gold Sheen Sapphire FIG Certificate No. 8918910210
Gold Sheen Sapphire FIG Certificate No. 8918910210
Gold Sheen Sapphire FIG Certificate No. 1281405425
Gold Sheen Sapphire FIG Certificate No. 1281405425
Gold Sheen Sapphire FIG Certificate No. 2071339944
Gold Sheen Sapphire FIG Certificate No. 2071339944
Gold Sheen Sapphire FIG Certificate No. 1022212017
Gold Sheen Sapphire FIG Certificate No. 1022212017


Gold Sheen Sapphire Price Update 2nd Half 2017

This is the price update for Gold Sheen Sapphire for the 2nd half of 2017. It covers the reported sale prices from the September Hong Kong and Bangkok Gem and Jewelry Trade Fairs.

I have made the following changes to the chart layout:

  • Removed ‘Sell’ and ‘Buy’ prices 
  • ‘Street’ is now ‘Trade Price’
  • Reporting periods are now half yearly, not quarterly. 
  • Added ‘5 Point Moving Average’ price

Since price data comes principally from major trade fairs, ‘Trade Price’ of pieces sold is a more reliable indicator of current price. There are enough data points now to give a meaningful moving average, this should provide a good trend indicator for the future price.

Gold Sheen Sapphire price 2nd half 17
Gold Sheen Sapphire price 2nd half 2017




Natural Ruby Cabochon Factory 2nds

Natural ruby with no heat for $15 per carat.

Over 300 pieces of natural ruby cabochons. No heat or any treatment. These are factory 2nds and all have eye visible surface defects and inclusions.

Weights are from 0.3ct to 29ct.

I will sell these for $15 per ct, or make an offer for the whole parcel.

Ruby Cabochons Factory 2nds
Ruby Cabochons Factory 2nds

Photo taken at midday with natural light.