The 125West Ruby is one of the world's largest known ruby crystal weighing in at 8.2lbs and amounting to 18,696 Carats. The Ruby crystal is semi-translucent to opaque and contains rutile. If cut en cabochon, this may create a six ray star. When exposed to long-wave ultraviolet light, the ruby displays a strong red fluorescence. It measures 122.4mm x 112.3mm x 133.9mm.
If you have doubts this gem is certified by the Gemology Institute of America Report 15171991 dated May 24th, 2006. If carved this Ruby would be the largest ruby curvature in the world. If cut en cabochon, the 125West Ruby would be the largest cut and polished ruby gemstone in the world.
Rubies have a long history as part of the mechanics of a watch. In 1702, Nicolas Fatio (Facio) de Duillier, a Swiss mathematician who was born in Basel, Switzerland, and Pierre and Jacob Debaufre introduced Jewel Bearings in watches to reduce friction. The jewels were not widely used until the middle of the 19th century. Until the 20th Century these jewels were ground from tiny pieces of natural gems. The watches had garnet and quartz, but it was the luxury top quality watches that used sapphire, ruby and even diamonds.
In 1902, a process to grow artificial sapphire crystals was invented, thereby making the jewels cheaper. In most modern watches, synthetic rubies (left image) are used between the moving parts, especially in the escapement and have a major effect on the timekeeping accuracy. It was discovered the harder the material used as bearings, the lessor the friction. Thus the ultra hard slick surface has a lower coefficient of friction with metal. In addition Rubies increase the life of the bearings. Rubies is the second hardest material after diamond and seven times harder than topaz. The Ruby belongs to the Coronado group of minerals, its name stemming from the red color (Latin: Rubeus). Red corundum is always called by the name Ruby whereas any other colors of corundum are known as Sapphires. The only difference between synthetic sapphire and ruby is as a result of the different impurities that have been added to change the color. There is absolutely no difference in their properties as bearings. Rubies can be opaque, translucent or transparent.
The very best watches have a 21 jewel movement; some have slightly more and some less. Some ETA movements use a 25 jewel movement which is a question of style rather than functionality.
The question regarding the number of jewels in a watch is a interesting one, and I will blog about it in due course.
As always let me know what you think about any points I bring up in the blogs. I love to hear feedback.