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Diamonds and rare gemstones are the ultimate form of concentrated wealth. Their size to value ratio makes them the most dense store of value out of all natural resources and other assets. Of limited and ever-decreasing supply important stones are nature’s  everlasting  marvels.  As  such  they  represent the utmost material  treasure and a unique investment proposition. At  Philippe  Petra  we stock a  highly  curated  selection of exceptional diamonds, unique colour diamonds and rare gemstones sourced from reputable suppliers as well as important private collections. We offer comprehensive sale, after-sale and consultancy services towards the acquisition of commendable investment-grade stones.



1. What are important stones?


Important or investment grade stones are rare, valuable stones who’s supply is extremely limited and demand is steady. Their durability is far greater than that of any other material goods, which enables them to stand the test of time. This particular combination of factors within rare minerals gives them the potential to retain their value or in many cases even increase in value exponentially over time. 


Aside from being available in extremely limited numbers in the market, stones that are considered investment grade are often no longer being mined or the amount mined is so insignificant (and expected to drop) that it  is unlikely for there to be more supply (of a sizeable nature)  in the future.


From an aesthetic perspective, important stones usually showcase exceptional naturally occurring features such as very good brilliance and clarity, exotic and highly saturated hues (or a complete lack of colour in the case of white diamonds) and meticulous cut among other things.


Examples of important stones are rare colour diamonds, high grade large white diamonds, Burmese rubies, fine Kashmir sapphires, fine un-enhanced Colombian emeralds, fine Feicui jadeite, rare colour gemstones and stones of historic importance and pedigree. 



2. What is the difference between high cost stones, rare stones and important stones?


While generic, expensive stones may decrease in value the day after they have been purchased and they may not necessarily have any potential for significant increment in value over time, important stones not only retain their value but they may double, triple or increase in value even more over time. Per instance, a round brilliant diamond in the 1.5-2 carat size range with a high clarity (VVS) and high colour (DEF) grades purchased from a retailer (offline or online) will come at a rather high premium but if the buyer decides to sell that same diamond say three years later, it is questionable whether he/ she would be able to get what he/ she paid for originally. 


On the other hand, rare stones may be desirable and hard to come by but that doesn’t necessarily mean they are that valuable. Their value may certainly increment over time due to lack of supply and relative demand but it will most likely not reach sums that are significant. For example, natural untreated turquoise with a high saturation is very rare and costly but it does not have the investment potential of a blue diamond. 


What differentiates important stones from any other stones lies in the unique combination of extremely low supply (at times only a few pieces  of a given stone may be available in the market), very high demand, outstanding natural characteristics, unparalleled durability and objectively high value. Important stones have a true pedigree, historically they have been coveted by kings, emperors and tycoons for their beauty and rarity but also their monetary significance.


3. What is a buyer advised to look for in important stones?


Below are several aspects to be taken into consideration when purchasing an important diamond or gemstone. When all or a few of the below aspects are met by any given gem, the latter is very likely to be an important/ investment grade stone. 


certificate: does the stone come with a recent and complete certificate from a  well reputed laboratory (i.e. GIA, Gubelin, SSEF)? Although what is detailed in a certificate is crucial in determining and authenticating the quality of a stone, one must give equal, if not greater importance to the eye-visible characteristics of the actual physical stone. 


origin of material: is the stone you are purchasing of natural origin and un-treated? If it has been treated, what is/ are the type(s) and extent of treatment(s)?


colour: is the colour of the stone commercially desirable, lively and with a medium-strong degree of saturation? If it is a white diamond in question, is the colour grade within the top of the range (i.e. D, E or F)?


crystal: is the gem's ‘crystal’ quality superior? Does it have noticeable brilliance? Is it relatively clear of inclusions and marks? Does the stone have a good light performance when viewed from the top?


finish: is the cut of superior quality? How good are the symmetry, proportions and polish of the stone? Does the cut permit the stone to showcase a good colour and brilliance when viewed from the top? Is the surface of the stone free from any undesired manufacturing marks?


geographic origin: in coloured stones and sometimes in fancy colour diamonds, origin will greatly affect price. Does the grading report indicate the geographic origin (country, region or mine) where the stone is believed to come from?


provenance: does the stone have a pedigree? Where was it sold previously? Who has owned it? Was it part of an important collection?


size: size or carat weight in itself does not have any relationship with quality, however important stones in larger sizes are extremely rare to come by and therefore highly prized. 


desirability: in market terms, are the shape, size, colour as well as other characteristics of the stone desirable? Is there a track record of the desirability of those aspects?


mounting: if the stone is already mounted in a piece of jewellery, how good is the design and craftsmanship? Usually important stones would not be set into cheap mountings. In addition, a cheap mounting may cause the stone itself to look cheap.


4. What types of stones does Philippe Petra carry?


At Philippe Petra we have highly curated selection of rare colour diamonds as well as important diamonds and rare precious stones. We can also assist our clients in sourcing particular stones that they may request. 


Our highly curated selections of stones are constantly updated and they may include:



Important type IIa diamonds (30 carats up)

Golconda and old mine cut diamonds

Fine fancy vivid yellow diamonds

Rare natural fancy coloured diamonds in different sizes



Fine natural unheated Burmese rubies

Fine natural unheated Kashmir sapphires

Fine natural Colombian emeralds (minor - no clarity enhancements)

Fine natural spinel

Fine natural Brazilian Paraiba type tourmalines

Fine natural Brazilian alexandrite

Fine natural unheated padparadscha sapphires

Fine natural Burmese jadeite

Fine natural salt water pearls

5. Where are Philippe Petra stones sourced?


We source our stones from reputable dealers, suppliers and mining companies as well as private collectors. 

6. Are Philippe Petra stones ethically sourced and conflict free?


Philippe Petra, has a zero tolerance policy toward conflict diamonds. Our diamonds are derived from legitimate sources that adhere to the Kimberley Process (KP) and are not involved in the funding of illegal conflict.

Through measures such as the KP, which tracks diamonds from mine to market, the diamond industry in partnership with Governments, the United Nations and NGO’s  controls diamond exports to avert trade of illegal diamonds.


At Philippe Petra we acquire diamonds from the most reputable suppliers, which enforce the KP. As an intrinsic company policy, we will continue to support and enforce any process that promotes legitimacy and transparency within the diamond trade, as well as any other minerals trade that we are involved with. All gemstones we trade are to the best of our knowledge derived from legitimate sources. For more information on diamond matters, please visit


7. Where are Philippe Petra stones cut?


Cut represents the way in which a diamond or gemstone is fashioned through lapidary processes. Measured by factors such as symmetry of facets and polish grade, cut quality is certainly one of the most important elements in diamond or gemstone quality as it will have a direct effect on colour and brilliance.


Philippe Petra directly or indirectly cooperates with the most reputable and experienced diamond and colour stone cutters Worldwide. Whether in rough state or already cut, the stones we acquire are analysed thoroughly by our specialists to ensure they are yielding the highest possible quality grades in terms of crystal quality, colour intensity and colour purity, light performance, brilliance, clarity and proportions. Philippe Petra does not operate sweatshop-type facilities and all our cutters whether in-house or outsourced are highly qualified professionals and they are treated as such. 


8. Are important stones sold loose or mounted into jewellery pieces?


Depending on each customer’s specific requests we sell our goods loose or mounted into  classic or custom-made high jewellery pieces.

9. Where are Philippe Petra high jewellery creations made?


Philippe Petra high jewellery pieces are made in different locations based on the nature and complexity of the work. Our pieces can be made in London, Paris, Athens, Florence and Hong Kong. The production time for a piece may range from one to twenty four months. 


Our high jewellery creations are entirely finished by hand using more than one hundred specialised tools. From conception to finished piece, the processes we employ in the making of our jewels are based on traditional methods aided by modern technology. 

10. How do we assist our customers in purchasing important stones?


Our highly curated colour diamond, diamond and colour stone selections are assessed by our specialists based on discriminating market-relevant criteria that reflect value and rarity. Prior to arranging a tailored viewing, customer-specific requests are carefully considered. These preliminary steps ensure the following:


a- the stones offered are of the highest grade of quality,

b- they are rare and collectible,

c- they are relevant to the customer,

d- they may have investment potential.


We do not employ sales people for the sales of our important stones and high jewellery but rather qualified diamond and colour stone experts that are very familiar with the high-end stone market and its trends.


We assist customers at every stage of the process, from sourcing or selecting a stone, to making a design, re-certifying the stone(s) if requested as well as anything related with transport and storage logistics and custom duties.

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