Wednesday, June 12, 2013

Famous Gemstones I

The American Golden Topaz, is a 172-faceted topaz weighing 22,892.5 carats. (4.5785 kg) It is the largest cut yellow topaz in the world, and one of the largest faceted gems of any type in the world. Originating from Minas Gerais, Brazil, it was cut by Leon Agee over a period of two years from an 11.8 kg stream-rounded cobble.
The Star of India is a 563.35 carat star sapphire, one of the largest such gems in the world. It is almost flawless and is unusual in that it has stars on both sides of the stone. The greyish blue gem was likely mined in Sri Lanka and is housed in the American Museum of Natural History in New York City.

The milky quality of the stone is caused by the traces of the mineral rutile, which is also responsible for the star effect, known as asterism. The tiny fibers of the mineral, aligned in a three-fold pattern within the gem, reflect incoming light into the star pattern.
The DeLong Star Ruby is a 100.32 carats oval cabochon star ruby, discovered in Burma in the 1930s.

On October 29, 1964, the DeLong star ruby was one of a number of precious gems stolen in a notorious jewelry heist by Jack Roland Murphy and two accomplices. The stone was eventually recovered at a phone booth in Florida.
The Andamooka Opal is a famous opal which was presented to Queen Elizabeth II in 1954 on the occasion of her first visit to South Australia. It was discovered in Andamooka, South Australia, an historic opal mining town. The opal was cut and polished by John Altmann to a weight of 203 carats.
The Arco Valley Pearl is a white 575 carats natural blister baroque pearl with pink and yellow overtones. It measures 79 x 41 x 34 mm. It is the largest natural pearl outside a museum and the second biggest ever. Mongolian emperor Khubilai Khan reportedly gave it to Marco Polo.