Effect exhibited on some minerals (usually only in polished cabochons) causing it to reflect a billowy, star-like formation of concentrated light which moves around when the mineral is rotated. Asterism is caused by dense inclusions of tiny, parallel, slender, fibers in the mineral which cause the light to reflect in such an interesting manner. Minerals that display asterism may exhibit four, six, and sometimes twelve rayed "stars", depending on the inclusions, size, and facet mode. Some specimens may display much stronger asterism than others, and some specimens may have areas where the inclusions are not present, leaving holes or empty areas in the star.
A named collection of stars in the sky that is not part an official constellation. Ex. the Big Dipper.
A grouping of stars resembling a familiar shape.
Asterisms are sub- or supersets of constellations which build a constellation itself, or a group of stars, physically related or not. Best known is the Big Dipper as a part of the Great Bear. But there are more than just this one. Click here for a table of asterisms.
any prominent star pattern that isn't a whole constellation (such as the Big Dipper).
A "star" or pattern of rays, typically six rays, crossing in a single spot on a cabochon cut gemstone when viewed under a single source of light. Star Sapphire is one of the best-known examples of a gemstone that exhibits the phenomenon known as an asterism.
A pattern of stars that is not an official constellation but appear within a constellation. Two example’s are the “Big Dipper” which is a portion of the constellation Ursa Major and the three prominent stars which form “Orion’s Belt” within the constellation of Orion.
The configuration of stars or "catch figure" used to identify a constellation. Example: the Big Dipper is the asterism for Ursa Major.
A luminous star like effect exhibited in some gemstones like star sapphires, garnets and rubies. asterismAsterism is caused by inclusions of tiny, parallel, rutile needles and may result in four, six or even twelve rayed stars. (Pronounced: as-ter-iz-mm)
A named group of stars that is part of a constellation, the Big Dipper is one.
(mineralogy) a six-rayed star-shaped figure seen in some crystal structures under reflected or transmitted light
(astronomy) a cluster of stars (or a small constellation)
a collection of stars (within a constellation ) that forms an apparent pattern from Earth
a designer jewelry star-like luminous effect that reflects light designer jewelry in some gemstones, like star sapphires and designer jewelry star garnets
a group of easily recognized stars that are a part of one or more constellations
a group of stars that make a pattern on their own, but are actually part of a constellation
a more recognizable part of larger constellation
a named grouping of stars which is not officially recognized as a constellation
a recognizable pattern of stars within or part of a constellation
a small easily recognizable formation of stars that is usually part of a larger constellation
a star pattern, and is different from a constellation
a subset or superset of stars which builds on the constellations themselves, like the Big Dipper as part of the Great Bear
An especially noticeable star pattern in the sky, such as the Big Dipper.
Star effect seen in some stones when cut en cabochon.
The star effect that you see in star sapphires or rubies, for example. This is usually caused by tiny silk rutile inclusions in the stone. The effect can be four- or six- rayed.
A star effect displayed by certain gems with intersecting inclusions.
Asterism or the Star Effect is a reflection effect that appears as two or more intersecting bands of light across the surface of a gem. This phenomenon is commonly found in Ruby, Sapphire and Garnet.
A notable pattern of stars, such as the Big Dipper, forming part of a constellation; not a constellation itself.
It is the effect which is exhibited on some minerals, generally in polished cabochons only, and causes it to reflect a billowy, star-like formation of concentrated light that moves around when the mineral is rotated. It is caused by the dense inclusions of tiny, parallel, slender, fibers in the mineral that cause the light to reflect in an interesting manner. Minerals which display the asterism may exhibit four, six, and sometimes twelve rayed stars, depending on the inclusions size and facet mode. Some specimens displays stronger asterism than others and some have areas where the inclusions are not present.
A special grouping of stars that are part of a constellation. These stars form recognizable figures in the sky. An example would be the Big Dipper. It is made up of stars in the constellation of Ursa Major also known as the Great Bear, but there are more stars in that constellation that are not part of the Big Dipper.
A stellar grouping which forms a familiar or recognizable pattern. For example, the Big Dipper is an asterism in the constellation, Ursa Major.
A recognizable grouping of stars which is a subset of a Constellation. For Example: 'The Big Dipper' is an asterism of the Constellation Ursa Major (The Big Bear) or 'Pleiades' is an asterism in the Constellation Taurus (The Bull).
A group of stars in a recognizable pattern that people commonly associate with each other, such as the Big Dipper or the Square of Pegasus. An asterism can be part of a formal constellation, or it can be formed from the stars of several constellations.
An optical phenomenon characteristic of starstones when cut en cabochon, producing a six-rayed star shape within the stone.
a small grouping of stars
A single ray, or multiple ray (star) effect seen on some cabochon cut gemstones.
A special apparent grouping of stars and part of a constellation, such as the Pleiades in the constellation of Taurus.
Star effect shown by some stones when cut.
Smaller constellation. See Lunar Mansions.
A group of relatively bright stars forming an easily-recognized pattern. Not constellations as such, asterisms often form part of constellations (such as the Big Dipper in the larger constellation of Ursa Major, the Great Bear), or encompass stars from more than one constellation (such as the Summer Triangle which consists of the brightest stars from three different constellations, Cygnus the Swan, Lyra the Harp, and Aquila the Eagle).
A group of stars that appear to make a recognizable shape, such as the Big Dipper.
The star effect displayed by certain gems with properly intersecting inclusions. Gems of this variety are always cut en cabochon (see Cabochon cut).
Named group for stars not identified as constellations
An asterism is a star-like luminous effect that reflects light in some gemstones, like star sapphires and star garnets.
Also know as the star effect, this is a reflection effect that appears as two or more intersecting bands of light across the surface of a gem. It is usually created through reflection of light by thin fibrous or needle-like inclusions that lie in various directions. There are 6 ray, 4 ray and, rarely, 12 ray stars. Ruby and Sapphire cabochons can sometimes very effectively show this phenomenon.
A gemological phenomenon in which the inclusions of certain polished gemstones produce a star effect when light is reflected off the surface.
The optical phenomenon of seeing a rayed figure in the form of a star. This is caused by the reflection of light from minute oriented and aligned needle-like inclusions.
A recognizable pattern of bright stars, usually (but not always) associated with a single constellation.
Four-rayed or six-rayed bands (cat’s eye) caused by light reflecting from needle-like inclusions within some gem crystals. (See Chatoyancy, Cat’s Eye and Tiger’s Eye).
Star effect seen on some stones.
A star-like light effect that is usually only seen in cabochons.
A star-like luminous effect caused by reflections of light in some stones, like Star Sapphires and Star Garnets.
This article is about the characteristic in some gems.
In astronomy, an asterism is a pattern of stars seen in Earth's sky which is not an official constellation. Like constellations, they are composed of stars which, while they are in the same general direction, are not physically related, often being at significantly different distances from Earth. An asterism may be composed of stars from one or more constellations.