Alexandrite Gemstone | Natural Alexandrite Stone - GIA
Alexandrite Gemstone is a rare variety of the mineral Chrysoberyl & is a strongly pleochroic gem. Color-changing alexandrite is nature’s magic trick.
Alexandrite Description - GIA
This 7.19-carat alexandrite was cut to feature its beautiful color change. When the light source changes from daylight to incandescent light, the gem’s color changes from bluish green to reddish purple. Alexandrite, with its chameleon-like qualities, is a rare variety of the mineral chrysoberyl ...
Alexandrite - Gemological Institute of America
Alexandrite can change colors under different kinds of light. For example, it can be green in daylight but can change to a brownish or purplish red under a lamp.
Alexandrite Gemstone | Natural Alexandrite Stone - GIA
A. GIA evaluates alexandrite but does not grade it. A GIA Colored Stone Identification & Origin Report assesses the characteristics of a mounted or loose alexandrite (weight, measurements, shape, cutting style and color), indicates whether it is natural or laboratory-grown and names any detectable treatments, and can issue an opinion on geographic origin, when possible and requested by the client.
Geographic Origin Determination of Alexandrite
2020年1月31日 · Figure 1. A group of rings featuring alexandrite from Brazil. Top row, left to right: A three-stone alexandrite ring with a 1.35 ct center oval flanked by two smaller ovals with a combined weight of 1.29 carats and a ring with a 1.32 ct kite-shaped center stone flanked by two kite-shaped diamonds weighing a total of 0.32 carats.
Alexandrite History and Lore - GIA
A 43-carat alexandrite in the collection of the British Museum. Abundant 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 gem was named after the …
Alexandrite Care and Cleaning Guide - GIA
Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or difficulty with which one mineral can be scratched by another. But the Mohs scale is deceptive. The steps between the minerals are not evenly spaced. For example, diamond is only one number away ...
Alexandrite Quality Factors - GIA
Alexandrite’s pleochroism makes it a challenge for cutters. When fashioning alexandrite, cutters orient the gem to show the strongest color change through the crown.
What’s a “created” alexandrite? - GIA
Laboratory-grown alexandrites are generally marketed with the name of the company and the word “created” rather than “synthetic.” The Federal Trade Commission Jewelry Guides permit the terms “laboratory-grown,” “laboratory-created” or “[manufacturer name]-created” to describe man-made materials.
亚历山大变石 | 天然亚历山大变石 - GIA
标记每个晶体边缘的切口被称为重入角。 宝石爱好者通常将其形容为“白天的祖母绿，晚上的红宝石”，亚历山大变石是金绿玉矿物中非常罕见的变色类别。 它最初在 19 世纪 30 年代被发现于俄罗斯的乌拉尔山脉，现在，斯里 ...