Gemology Hub | Gemstone & Mineral Identification Guides

  Iris agate is agate whose thin section shows spectral colours when viewed in transmitted light. These colours are not thin-film colours such as those of precious opal. Specimens of iris agate were observed in 1933 by Fred S. Young. Iris agate   In 1935 when Fred S. Young and Dr. H. C. Dake first showed the author thin slices of iris or rainbow agate, the display of colours recalled the similar appearance of a diffraction grating. Microscopical examination soon confirmed the opinion that a periodic banded structure existed in the agate, and revealed interesting correlations with the chalcedony's structure and variations in fineness and regularity. No satisfactory explanation of the formation of this regularly banded structure has yet been devised although the theory proposed by Hedges  may apply in a general way. Iris agate from Mexico                                       ...

A rare and beautiful type of Coral found near the Galapagos Islands, Ecuador.

The Great Table diamond was first reported by gem merchant Tavernier in 1642. In Tavernier’s list of the “largest and finest diamonds and rubies seen by him in Europe and Asia,” the Great Table appears third. Of it he remarks: “It is a stone which weighs 176 1/8 mangelins, which make 242 5/16 of our (old) carats. When in Golconda, in the year 1642, I was shown this stone, and it is the largest diamond I have seen in India in the hands of dealers. The owner allowed me to make a casting of it, which I sent to Surat to two of my friends, calling their attention to the beauty of the stone and to its price, which was 500,000 rupees. I received a commission from them to offer 400,000 rupees for it, but it was impossible to come to terms at this price.” Tavernier’s accompanying illustration shows the Great Table to be table-cut, so that it may be easily recognised should it again come to light in India or elsewhere but a popular theory suggests the diamond has been broken up and has not been ...

 Worldwide Gemological Laboratories Contact Information Accredited Gem Appraisers Address : 730 Sansom St., Philadelphia, PA-19106, USA. Telephone : 215-873 Email :  info@gemappraisers.com Website :  http://www.gemappraisers.com AGT Gem Laboratory Address : Tokyo: 5-15-14 Ueno, Taito-ku, Tokyo Building 2F CY Okachimachi Osaka: Minamisenba 2-5-8, Chuo-ku, Osaka Building community Nagahori Telephone : Tokyo: (+81)03-3834-6586 / Osaka: (+81)06-6266-8601 Email :  info@agt.jp Website :  http://www.agt.jp/ AGT Gem Laboratory is a website that provides services related to the inspection and grading of diamonds and other gemstones. They issue reports to ensure the safety of the jewelry industry and consumers. They also offer seminars to educate people about gemstones. The website includes information about their services, reports, seminars, and knowledge about gemstones. They have a membership program, and their contact information is available on the website. The websi...

Quartz is the second-most abundant mineral in the Earth’s continental crust, after feldspar. It is made up of a continuous framework of SiO 4  silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO 2 . There are many different varieties of quartz, several of which are semi-precious gemstones. Throughout the world, varieties of quartz have been since antiquity the most commonly used minerals in the making of jewellery and hardstone carvings. The quartz group includes a number of different species/varieties. There are two categories crystalline quartz and cryptocrystalline quartz (chalcedony). Source:  en.wikipedia.org/wiki/Quartz Cause of Color:  Rose Quartz: Charge transfer reaction (Ti 4+  and Fe 2+ ) as a result of irradiation. Chemical Composition :  Silica (Silicon Dioxide) SiO 2 Crystal System / Forms :  Trigonal System Prismatic with pyramidal terminations (rhombohedron, trapezohedron, trigonal, ...

Name: corundum Class: Oxide/Hydroxides Chemistry: Al2O3 Color(s): red (ruby), blue (sapphire), gray, black, yellow, purple, (just about all colors) streak: white Hardness: 9 SpecGrav: 3.9 - 4.1 Fracture: tough Cleavage: none Crystal: hexagonal Envronment: in pegmatites, in contact metamorphics, and in other metamorphic terrains. Association: Locals: |Burma | China | Sri Lanka | NC, Mo., USA | Misc: The name comes from the ancient Sanskrit, ³kuruvinda² meaning ³ruby². It is derived from the Tamil ³kuruntam², which also came from the Sanskrit. Do to its hardness it is also used as an abrasive. C

1. Vinegar What You Will Need ¼ cup vinegar 2 tbsp baking soda Warm water Processing Time 5-10 minutes Process Mix all the ingredients in a bowl to make a thick paste. With an old but soft toothbrush, rub the paste all over your diamond ring or jewelry. Continue to do this for a few minutes. Rinse it with tap water and pat it dry. Alternatively, you could soak the jewelry in vinegar for about 5 minutes before you go ahead and clean with the paste. 2. Baking Soda What You Will Need 2 tbsp baking soda Warm water Processing Time 5-10 minutes Process Take about 2 tbsp of baking soda and add a little water to it to make a thick paste. You can replace water with white vinegar (optional). With an old toothbrush or a scrub, apply this paste to the jewelry you plan to clean. Scrub carefully. You will start to see the dullness diminish and your jewelry piece begin to shine. Rinse it with water and repeat this procedure if needed. Avoid using them on anything with enamel, gemstones or pearls. 3. ...