|It made $2m at auction.||Napoleon’s talisman was commissioned in 1800 after his Egyptian campaign. The talisman was lost in the Battle of Waterloo in 1815. During his retreat from the battlefield, his abandoned personal carriage was captured by a Prussian major. Deeply superstitious, Napoleon spent two years planning the intricate design of the jewels in the piece. Napoleon’s sphinx was dug up just after WWII in Noordwijk in the Netherlands, around 200 km from the Waterloo Battlefield.|
Sunday, 1 August 2021
Wednesday, 28 July 2021
|Demantoid gets its name from the Dutch words for “diamond-like.” The stone owes its brilliance to two factors: A high refractive index and a high dispersion. Demantoid’s dispersion rating is the highest of all gemstones, including diamond. Known for their brilliant green color and fiery dispersion, demantoid garnets are unique because their inclusions, usually seen as flaws in other gems, are highly coveted.|
|Demantoid garnet is mined in other parts of the world, including Iran, Namibia, Pakistan, Italy, Madagascar and Canada, but Russian demantoid sets the mark by which all the others are compared.
Demantoid garnets are rarely found in sizes larger than 2 carats.|
Tuesday, 27 July 2021
|Spinel is magnesium aluminum oxide with the formula MgAl2O4. The name "spinel" comes from either the Latin word "spina" meaning "thorn", due to its characteristic octahedral crystals having pointed ends, or the Greek word "spintharis" meaning "spark".|
Although spinel occurs in a range of different colors, the pink to red variety is the one that is commercially important. Spinel is single refractive and doesn't have pleochroism. It belongs to the cubic crystal system with hardness of 8.0 on the Mohs scale.
| Spinel offers a range of hues from orange to intense red, vibrant pink, and all shades between purple, blue and violet through to bluish green.|
|Historically, the most famous red spinels came from the Balas region of Afghanistan and were known as Balas rubies. Some of the most famous rubies in the world, such as the Black Prince's Ruby, part of the British Crown Jewels, are actually spinels. More recently, Sri Lanka and Burma has been the main source for fine spinel.|
The highest quality transparent blood-red "ruby spinel" and hot-pink spinel has come from mines in Mogok, Upper Burma.
|In 2007 several huge spinel crystals were discovered at Ipanko, near the town of Mahenge, in Tanzania. Miners unearthed spinel crystals weighing from six to 54 kg. |
|The spinel crystal displayed the vibrant pink color that is now famous from Mahenge Spinel. Thousands of carats of gem quality gems were cut in Thailand and distributed into the world market.|
From this point on Mahenge Spinel was thrust into the world spotlight.
|Spinel is highly sought after by gem connoisseurs, and well-formed spinel crystals are in high demand among collectors. Red spinel range from orange-red to purplish red, with pure red considered the finest of all.|
A top-quality 5 carat red spinel might sell for around a tenth the price of an equivalent-quality ruby, and pink spinel often sells for less than pink sapphire.
|Tanzania is now the world's second largest supplier of spinel in the pink-to-red range. Spinel also has been found in Ipanko and Matombo. |
Since the Mahenge spinel is still a recent discovery, there is still top quality material available for collectors.
Weathered marble outcrops tower over the spinel diggings of Ipanko, near Mahenge.
Saturday, 24 July 2021
Described by gem aficionados as “emerald by day, ruby by night,” alexandrite is a very rare color-change variety of the mineral chrysoberyl.
|Alexandrite deposits were first discovered in 1830 in Russia’s Ural Mountains. Those first alexandrites were of very fine quality and displayed vivid hues and dramatic color change.|
|The spectacular Ural Mountain deposits didn’t last, and today most alexandrite comes from Sri Lanka, East Africa, and Brazil. The newer deposits contain some fine-quality stones, but many display less-precise color change and muddier hues than the nineteenth-century Russian alexandrites. Fine alexandrite is green to bluish green in daylight and red to purplish red in incandescent light. Alexandrite is most often available in mixed cuts. Its extreme rarity means it is often cut to save weight.|
|Good quality alexandrite has few inclusions. Rarely, needle-like inclusions create a cat’s-eye. Most cut gems weigh less than one carat. Larger, high quality gems rise in price dramatically. Production from Russian mines is very limited today. Sri Lankan alexandrites are generally larger but their colors tend to be less desirable. Alexandrites from Brazil have been found in colors that rival the Russian material, but production has decreased significantly.|