pleochroic
The luminous property that some minerals and gemostones have, whereby they appear to have more than two colours particularly when viewed from different angles ...
[Pleochroic Gems: an iolite showing a lot of its undesirable grey axis, an iolite oriented to show a near ideal blue-violet, a "tourmaline cut" gem mounted in a "tourmaline mount"] ...
Pleochroic
Term used to describe a gem that appears two or more different colors or shades when viewed from different directions.
Poison Ring ...
pleochroic haloes around zircon inclusions
Surface Luster
vitreous to adamantine ...
Pleochroic colors- Blue, violet and pale yellow usually seen simply as almost colorless and deep blue.
Refractive index- 1.54 to 1.60
Specific Gravity- 2.57 to 2.61
Blue Glass ...
Sapphire is pleochroic, displaying a lighter and more intense colour when viewed at different angles. Some pleochroic Sapphire is blue when viewed at one angle, and purple at a different angle.
Andalusite is pleochroic, i.e. it shows different colours in different directions. When cutting most pleochroic gemstones, such as iolite and tanzanite, the trick is to minimise the pleochroism and maximise the single best colour.
This stone is pleochroic in nature and poses a challenge for the gem cutters. To bring out the color of this stone is a real tough job.
As one rotates a pleochroic gem, the eye blends the two colors together, but differences will be seen in different directions.
Kunzite is strongly pleochroic (displaying color intensity variation of many colors), which is strongest on the kunzite crystal when viewed from the top or bottom.
Iolite crystallizes in the orthorhombic system and is highly pleochroic. Changes in color, or intensity of color can be seen when the stone is rotated and viewed at different angles. Iolite is moderately hard at 7 to 7.5 on the Mohs scale.
It is characterized as a pleochroic gemstone, meaning that it has different colors as the stone moves in different directions.
This mineral also exhibits the pleochroic qualities; i.e., X-axis showing clear yellow, Y-axis showing dark violet, blue, or brown, and the Z-axis showing clear blue.
Due to its strong pleochroism, darker tourmalines are cut to display the lighter of the two pleochroic colors. This means orienting the c-axis of the crystal parallel to the table facet.
In minerals with only two rays, two pleochroic colors can be detected, called dichroism.
It is pleochroic, which means it displays all its different orange, brown, yellow, green and golden colours in different directions at the same time.
In most cases, the color variations are not obvious to the unaided eye and must be viewed through a polariscope or dichroscope, but in some cases, the pleochroic colors are strikingly obvious.
Andalusite is highly a pleochroic gemstone, that is the angle of light refraction makes the wide array of colors seen in the stone. Typical colors include green, brown, red and yellow.
Hiddenite is strongly pleochroic, meaning there is a color intensity variation when a crystal of it is viewed from different directions. Hiddenite is an attractive gem mineral, but is rare and for the most part known only to collectors.
Tourmaline is strongly pleochroic: the darkest color is always seen when looking down the axis of the crystal, and the challenge for the gem cutter is to orient the stone in such a way as to get the best color possible while avoiding inclusions.
Often described as pigeon's blood red, this gem is pleochroic in nature i.e., exhibiting more than two colors when viewed from different angles. (Tints of purple or brown are visible).
Hiddenite is the strongly pleochroic, bright green variety of spodumene. First discovered in North Caroline by W. E. Hidden in 1879.
Gemological information
Gemological Information for Hiddenite
Color ...
Rock-forming deposits of strongly pleochroic lusakite, a deep blue opaque staurolite, where cobalt and magnesium replace iron, are located in Lusaka, Zambia. The lusakite is extracted from the formations and used as a pigment.
Tsavorite isotropic
Tourmaline v. strongly pleochroic
Peridot R.I.=1.65, Emerald R.I. = 1.57-1.58, colors usually quite different (more yellow in peridot)
PINK STONES: Tourmaline vs. Spinel vs. Sapphire vs. Morganite ...
Iolite is a form of cordierite. It is pleochroic, which means
that it appears dark blue when viewed from one direction
and, when it is turned, it can appear almost colorless.
Iolite is also popularly known as "water sapphire." ...
Iolite is pleochroic; a single stone will show many colors (in the case of Iolite, violet-blue, light blue, and yellow-gray). Iolite is not rare and has a hardness of 7 - 7.5. Iolite is found in Sri Lanka, India, Madagascar and Burma.
Harder than all other gemstones save diamond and corundum, chrysoberyl is strongly pleochroic, meaning different colors - such as red, orange-yellow, and green - appear depending on which angle you view the gem from.
Pleochroism is the property of having more than two colors, especially when viewed from different angles. In pleochroic minerals, a single stone will show many colors (in the case of Iolite, violet-blue, light blue, and yellow-gray will be visible).
Gemstone Physical Characteristics: Iolite crystallises in the form of masses, grains, and short prismatic crystals. It also exhibits pleochroic qualities.
Tourmaline crystals are beautiful, pencil thin and ridged, and they are also sometimes set in jewelry. Some designers also set rainbows of tourmaline in each color of the spectrum. Tourmaline is strongly pleochroic: the darkest color is always seen ...
meaning the gemstone changes colors depending which angle it is viewed from. Cordierite displays colors ranging from deep blue, to violet and light blue and grayish blue. It can be confused with tanzanite (zoisite) which is also strongly pleochroic.
The pleochroism is strong, the pleochroic colors being usually green, yellow and brown. Clinozoisite is white or pale rose-red variety containing very little iron, thus having the same chemical composition as the orthorhombic mineral zoisite.
Pleochroic - Showing different colors when a crystal is viewed from different directions.
Plumose Habit -- A feather-like habit.
Prism - A crystal face intersecting lateral axes, and parallel to the vertical axis.
 See also: Color, Stone, Mineral, Gemstone, Crystal
  
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