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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 ...
Stones that show a dramatic color change and strong colors (e.g., red-to-green) are rare and sought-after, [8] but stones that show less distinct colors (e.g. yellowish green changing to brownish yellow) may also be considered "alexandrite" by gem labs such as the Gemological Institute of America. [13] [14]
Synthetic alexandrite is an artificially grown crystalline variety of chrysoberyl, composed of beryllium aluminum oxide (BeAl 2 O 4). The name is also often used erroneously to describe synthetically-grown corundum that simulates the appearance of alexandrite , but with a different mineral composition.
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The Oregon Vortex is a roadside attraction that opened to tourists in 1930, [1] located on Sardine Creek [2] in Gold Hill, Oregon, in the United States.It consists of a number of interesting effects, which are gravity hill optical illusions, but which the attraction's proprietors propose are the result of paranormal properties of the area.
Dispersion: 0.017 [1]: Ultraviolet fluorescence: Pink stones; inert to very weak red to violet in long and short wave [1]: Absorption spectra: Strong narrow band at 498 nm, and almost complete absorption of red down to 640 nm in blue and green stones; red and pink stones show lines at 458 and 451 nm, as well as a broad band in the green spectrum [1]
A circumhorizontal arc is an optical phenomenon that belongs to the family of ice halos formed by the refraction of sunlight or moonlight in plate-shaped ice crystals suspended in the atmosphere, typically in actual cirrus or cirrostratus clouds. In its full form, the arc has the appearance of a large, brightly spectrum-coloured band (red being ...
A mirage of an astronomical object is a meteorological optical phenomenon, in which light rays are bent to produce distorted or multiple images of an astronomical object. The mirages might be observed for such celestial objects as the Sun , the Moon , the planets , bright stars , and very bright comets .