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The Alexandrite effect has also been observed in some other minerals, such as fluorite, sapphire, kyanite, monazite, spinel, garnet, tourmaline, and rare-earth oxalates. Not to be confused with the alexandrite effect, some minerals also exhibit pleochroism. The former is a response to different wavelengths of light in general, the latter an ...
Flux-grown alexandrite stones are expensive to make and are grown in platinum crucibles. Crystals of platinum may still be evident in the cut stones. Alexandrite grown by the flux-melt process will contain particles of flux, resembling liquid “feathers” with a refractive index and specific gravity that echo that of natural alexandrite. Some ...
Hydrothermal lab-grown alexandrite has identical physical and chemical properties to real alexandrite. [18] Some gemstones falsely described as lab-grown synthetic alexandrite are actually corundum laced with trace elements (e.g., vanadium) or color-change spinel and are not actually chrysoberyl.
The pink color of tourmalines from many localities is the result of prolonged natural irradiation. During their growth, these tourmaline crystals incorporated Mn 2+ and were initially very pale. Due to natural gamma ray exposure from radioactive decay of 40 K in their granitic environment, gradual formation of Mn 3+ ions occurs, which is ...
Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear gradually to change colour as the angle of view or the angle of illumination changes. Iridescence is caused by wave interference of light in microstructures or thin films.
A rarer type, which comes from the Mogok area of Myanmar, features a vanadium chromophore, the same as is present in Verneuil synthetic color-change sapphire. Virtually all gemstones that show the "alexandrite effect" (color change or 'metamerism') show similar absorption/transmission features in the visible spectrum. This is an absorption band ...
For 30 years, Rose Bowl co-host Leeza Gibbons, 67, had a near-constant presence on network television. From 1984 to 2000, she was a correspondent and co-host of Entertainment Tonight, and the host ...
Thermochromism is the property of substances to change color due to a change in temperature. A mood ring is an example of this property used in a consumer product although thermochromism also has more practical uses, such as baby bottles, which change to a different color when cool enough to drink, or kettles which change color when water is at ...