Difficulties with photographing gold sheen sapphire
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.
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.
At this point there is no doubt it is synthetic ruby. A very nice gem, but worth maybe $30 at most.
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.
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: https://sjwgems.com/wholesale/ or email gss@sjwgems.com.
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 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.
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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.
Photo taken at midday with natural light.
New Diamond Cut Gold Sheen Sapphire
New Gold Sheen Sapphire ‘diamond cut’ direct from the factory from carefully selected highest grade rough.
After careful selection of the rough, about 10% of material is suitable for this high grade faceting. Once faceted, only one or two pieces in 10 make this selection. Most pieces show colour change from metallic copper/gold in incandescent light to blue/green in natural light.
While most pieces come opaque, typical of Gold Sheen Sapphire, about 20% come as translucent with yellow, green/yellow and gold hues.
All are available in all calibrated sizes from 3mm to 10mm, or can be cut to order.
Movement in Gold Sheen Sapphire Price
The first and second quarter of 2017 have seen some interesting movement on the price of gold sheen sapphire.
The price for top grade stones has increased slightly in Q1 and remains stable though Q2. Meanwhile prices for all other grades took a dip in Q1 and remain constant in Q2, with the exception of the street price of grade 2 stones which improved in Q2.
It seems clear that the market is becoming more discerning, reflected in the willingness to pay for best quality material. The trend has been for increasing sales from repeat buyers, which have exceeded reported sales from first time buyers for the first time in Q1, and continuing into Q2. This is further reflected in the price drop of lowest grade material, where buyers have been able to negotiate pricing based on large volume orders.
Special promotions for new cutting and polishing techniques as well as the introduction of new cut types and increased presence at trade shows have all contributed to fluctuations in mid to high grade pricing.
Price Chart Key:
- Grade 1 – No surface defects, no structural defects, or ‘very rare’
Grade 2 – Eye clean surface, no structural defects, or ‘rare’
Grade 3 – Minor surface defects, minor structural defects. or ‘common’ - Anything less than Grade 3 is not available for sale and either discarded or re-cut.
- “Buy” is the wholesale price for Grade 3 stones in large quantities over 10,000 carats
- “Sell” is the price offered for sale from retail or trade fare for single stones or small sales.
- “Street” is the negotiated price for small quantities of stones of various grades.