The 6.16 carat Farnese Blue - a historic diamond that has witnessed more than 300 years of European history - was graded Fancy Dark gray-blue by GIA. Like the Hope diamond, it was most likely mined in the Golconda region of India, which was the world's most important source of diamonds until diamonds were discovered in Brazil in the 1720s.
The Farnese Blue was given by the governor of the Philippine Islands to Elisabeth Farnese, the new Queen of Spain, in 1715. It passed down over the next three centuries through some of the most splendid royal families in Europe. Seen here is the Farnese Blue set against an antique silver plaque that details its ownership. Want to learn more about blue diamonds? | Photo: Martha Altobelli/GIA. | Pink Spinel or Red Diamond? | Both natural diamond and spinel crystals can form as octahedrons and show triangular etch marks, called trigons, which are caused by chemical dissolution in the earth. Perhaps that is why a client submitted a 0.50 carat rough crystal with a remarkably saturated Fancy Intense to Vivid pink color to the GIA laboratory in New York for a Colored Diamond Identification and Origin Report.
GIA scientists quickly realized that this was not a diamond, however. This crystal shows a distinctive conchoidal fracture amid the trigons, something that diamonds never show. This feature, along with the sample's striking color, indicated something other than diamond. After testing, it was revealed that this stone is actually a natural pink spinel. | Courtesy: Paspaley Pearls Pty Ltd. | Before pearl culturing techniques were perfected and cultured pearls became widely available, natural pearls were some of the rarest and most sought-after treasures in the world. Revered as tears of the gods by the ancient Persians and used as talismans against fire by the ancient Chinese, natural pearls symbolized perfection to many because they emerge fully formed from mollusks and do not require faceting or other major human intervention to finish them.
From Queen Elizabeth I to Chinese emperors, they were worn as symbols of wealth and power. Natural pearls are still treasured today for their fascinating origin. The pearls seen here are from Paspaley's natural pearl collection collected in Australia. How does GIA separate natural from cultured pearls? We use X-ray techniques such as real-time microradiography (RTX) and X-ray computed microtomography (μ-CT) to analyze a pearl's internal structure. Want to explore the origin of natural pearls? | We hope our gem knowledge inspires you to rock on. #knowledgerocks | |
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