Up until April of 2017, the famed Oppenheimer blue diamond was the most expensive jewel ever sold at auction. The rectangular cut 14.62 carat blue diamond was the coveted premier lot at the Christie's Magnificent Jewels event in Geneva (2016).



Named after its previous owner Philip Oppenheimer, it's considered as the largest fancy vivid blue diamond ever shown at auction. The stone sold for just a bit over 50 million dollars after two telephone-bidders ended a competitive bidding war for its ownership.

Today fancy blue diamonds are among some of the most trending luxury gemstones chosen for spotlight unveiling at many international auction events. They outrank equivalent-clarity graded colourless diamonds in price per carat many times over due to rarity and exclusivity even among aristocratic collectors.



The Oppenheimer family name is historically linked with the diamond trade's rise to popularity. At one point in time, their family controlled the De Beers Group and its mining operations, which pioneered large-scale South African diamond sourcing and coined the famous tagline- "A diamond is forever".

What are the most preferred carat sizes for people here in the city? Well, since we've asked around about color, shape and clarity preferences, it would only be right to complete the survey with asking Filipinos how big they want their diamonds to be.




Naturally, we had some light-hearted joking that followed this question, such as replies like "as big as a golf ball!" or "like a closed fist". Obviously people do appreciate carat sizes here in the Philippines, as visual presence is one of the things people look for in a diamond purchase.



Although joviality aside, there was a balance to the ratio of price versus carat size. Our population seemed to be split into three groups when it came to their most favored selections. Some preferred sizes of a third to one half carat, but wanted several stones in a single jewelry piece to make its appearance appear bigger and brighter. These "illusion" style arrangements are quite popular here in our country at the moment.

Other interviewees told us that they would only buy stones that weighed 1 carat or more, but maxed out the range at 2.5 carats. These sizes were fast-moving, and still held considerable value as hard asset investments. It's quite practical to consider both of these selections actually.




The last grouping wanted stones that ranged from 2.5 or 3 carats to 5 carats. This group was smaller in quantity, but represented those who took diamond-buying to the next level. Large stones in this range were still moveable in the trade, of course, but here in the Philippines they might not be as fast-moving as smaller stones due to relatively higher prices. These gems are serious investments and can fetch up to millions of pesos (in the correct color and clarity grade levels).

Most buyers in the Philippines seem to prefer stone sizes that are either "small" (0.50 ct. or lower), but could be made to look bigger through specific jewelry setting designs, or "solitaire" carat sizes (1 ct. , 2 ct. or 5 ct.) that hold more substantial investment value, but are considered as fast-moving assets due to high demand on the market.

Diamonds with larger carat sizes are rarely seen, even here at the laboratory. Stones of 10 or 15 carat sizes could cost as much as a small house, or several condominium units. Most filipinos would rather diversify their purchases if granted this much flexible spending power. Still though, to possess diamonds of this size is rare, and can be a powerful status symbol in the highest societies of the country.



One thing we observed accidentally though, is that a lot of Filipinos tend to assume that larger stones are automatically imitations. The mentality of "it's too good to be true" kicks in, and the dismissive assumption fills their minds quite quickly.

Carat size is one of the 4C's of diamond quality, and we'll be teaching more about it soon, when we reveal the schedule for our upcoming gemstone identification and diamond grading workshops.

There are some measures that you can take in order to eliminate common imitations like glass or plastic from your stone's possible identifications. Here, we present the steps needed for basic gemstone evaluation, pre-grading. It's much easier to detect certain simulants over others, however practice is highly recommended under the tutelage of an experienced gemologist, so as to not make a crucial mistake in your identification.

The process of initial gem identification, makes use of studying a stone's specific gravity, hardness, optical density and the presence of inclusions. Interpreting these observations in the context of gemology can help separate real gemstones from their fake counterparts.

1. Check your Gemstone's Heft by Bouncing it on Your Palm.

Using your open palm, bounce the stone around the center of your hand to get an idea of its heft. Every gemstone has a property called specific gravity that will determine how much it weighs at a certain volume or size. Even an average person can use an item's heft to rule out lighter imitations such as transparent gemstones made from plastic. The presence of mould lines or mould marks on facet surfaces can also help to give plastic or resin imitations away.

2. Search for Rounded or Curving Facet Junctions.

Look at the edges of your stone's individual facets. Some glass imitations will give you the impression of having rounded facet junctions, which would never be observable in a natural gemstone. This is because natural gemstones are mined from the earth and cut using hard abrasive materials. They therefore get very sharp facet edges in the process. Certain glass imitation gems are actually molded from molten silica material. An evidence of this would be that their edges are more curved than they ought to be.

3. Loupe Your Stone, Check for Any Inclusions at All.

Examine the interior of a stone with a 10x triplet loupe. A standard magnifying glass is not enough. Loupes are the minimum requirement for studying the inclusions within a gemstone. Certain inclusions can prove that a gem actually came from deep beneath the earth. Other inclusions, or a lack of them, can also sometimes indicate that a stone was synthesized in a laboratory. This may take practice and experience, but observation under magnification is one of the most reliable ways to identify gemstone species.

4. Consider the Design, Craftsmanship and Markings of its Setting.

Examine the metal setting of a gemstone if it is already mounted on a piece of jewelry. Sometimes the design can help give you clues about the stone itself. Large, brilliant stones with intense saturation should not be seen on metal mountings that are poorly constructed. Hallmark stamps can also be clues in your identification process. Silver settings are often stamped with a '925' mark, for 92.5% silver, the requirement for sterling silver. A five carat natural, untreated diamond for example, would be an unlikely sight on a silver banded ring. All these indications are not 100% however, only hints that can definitely help you make a smart estimate of your stone's nature.

5. Observe and Note Down the Hardness of Your Stone's Surface.

Check for any signs of wear-and-tear or scratches. Certain gemstones like diamond, are actually very hard. These stones would be less likely to display abrasions along facet junctions, or multitudes of scratches on the surface. Use reflected light to observe the texture of a stone's facets. Bumpy or "orange peel" texture is also an indication that the stone may be a moulded glass imitation.

6. Determine the Other Properties it Possesses as a Mineral.

If you possess a gemological setup, such as a desktop refractometer, polariscope and spectroscope, you can study a material's unique properties and use this information to deduce its identity. Although this sounds simple enough, it does require a considerable familiarity with the field of gemology. If you are uncomfortable taking or interpreting this information, or lack the necessary instrumentation, find a third-party laboratory to do it for you. Eliminate the guesswork with facts and science. Feel free to contact our laboratory gemologists for assistance on your stone.



Be very cautious about using handheld 'diamond testers', these make use of thermal conductivity (some use electric conductivity), and do possess a lot of limitations on their usage and precision. Thermal-based diamond testers, as well as many dual testers can misidentify moissanite as diamond. Neither instrument is also able to detect evidences of a stone being man-made, i.e. lab-grown diamond will fool them easily. Gain awareness above the marketing of these tools. They are useful in their own right, but not foolproof by any means. The misuse of tampered, outdated, or even standard testing instruments is especially rampant here in the Philippines today.