RusGems Created Gems

Alexandrite Czochralski method

RusGems offers created Alexandrite, which is produced using the Czochralski method. Only this method enables creation of the large and pure crystals of recrystallized sapphire.

It is almost impossible to distinguish the crystals obtained thus from natural ones by only using simple methods (refractome-ter, polariscope, microscope, spectroscope, etc.). Crystals grown by Czochralski method belong to a group of high-quality expensive synthetic stones, which are also called recreated or cultivated stones (created or cultured gemstones).

Alexandrite is one of the most amazing stones. The main difference between alexandrite and other gemstones lies in its unique ability to change color depending on ambient light. Alexandrite has a bluish-green or grass-green color when white fluorescent artificial lighting is used, but turns violet or ruby-red in sunlight or candlelight. This is called the alexandrite effect phenomenon, and is commonly used with other minerals that are able to change color. For example, garnets, which can change color, are also called garnets with alexandrite effect.

Alexandrite is a variety of the mineral chrysoberyl. The unusual color change effect is due to the presence of chromium ions in the crystal lattice. Currently, natural alexandrite is recognized as one of the most beautiful and rare gems. Of course, this led to the appearance of forgeries in the market, which only remotely resemble the original stone as they fail to reflect the great color changing effect and light play inside natural alexandrite. Corundum forgeries are very widespread.

RusGems developed a high level of modern chemical technology to grow crystals. This process achieved excellent results and allowed the growth of recrystallized alexandrite, not the corundum forgery. Our technology permits the creation of completely pure crystals with a size up to 100 mm in length and 30 mm in diameter. Alexandrite crystals of two different varieties are grown in our laboratory. Technologies differ only in terms of outlook of created crystals. We are able to grow boules as well as HDSM sheets, which represent a better fit in terms of gem-cutting technology. All properties of recrystallized alexandrites of both kinds, which are created by RusGems, are completely identical to the ones of natural alexandrite.

Properties Alexandrite by RusGems Natural Alexandrite
Classification Chrysoberyl Chrysoberyl
Chemical formula BeAl2O4:Cr3+ BeAl2O4:Cr3+
Crystal system Rhombic Rhombic
Color changing effect Bluish-green/Magenta Bluegreen, grass green/purple and red, crimson, pink
Hardness (Mohs) 8.5 8.5
Density 3.7 3.6-3.8
Refractive index 1.741-1.75 1.741-1.759
Dispersion 0.015 0.015
Inclusions Inclusions free. Grade of quality with inclusions upon request Fogs, cracks, holes, multi-phase inclusions, quartz, biotite, fluorite
Size of crystals Boules: diameter of 20-30 mm, length of 40-100 mm
Flat sheets: thickness of 20-30 mm, length of 80-120 mm
Usually 1-5 mm in size, rarely 5-20 mm in size
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Rough stone is always available