INTERGROWN
Intergrown crystals occur when two mineral crystals grow together and become one.
INVERALL SAPPHIRE ...
Magnificent intergrown brown topaz crystals from the Mogok region of Burma. 8.5 cm. high. William Larson collection. Photo: Jeff Scovil ...
GALENA - Leadhills.
Intergrown cubo-octahedral xtls. to 2cms.
CALCITE - New Glencrieff Mine, Wanlockhead.
A 25mm scalenohedral crystal speckled with pyrite crystal inclusions.
penetration twinning Form of twinning where two or more crystals are intergrown. Examples: fluorite twin, carlsbad twin, staurolite twin, and swallowtail twin. Pentagonal dodecahedron Synonym of pyritohedron.
Penetration Twin - A twinned crystal where one crystal has intergrown with another. (Fluorite, Pyrite)
Perky Box -- A cubic-shaped plastic box with a black base, used for mounting thumbnail specimens.
Crystals from this source are so intergrown with ilminite inclusions oriented parallel to the base that they exhibit a bronze luster and show a weak golden asterism.
In nature quartz crystals are often twinned, distorted, or so intergrown with adjacent crystals of quartz or other minerals as to only show part of this shape, or to lack obvious crystal faces altogether and appear massive.
All jade is composed of fine-grained, highly intergrown, interlocking ("matted" or "felted" texture, like asbestos or felt) crystals of one or both of these minerals.
Chryscolla usually occurs as a bright green or bluish crust. Crystals intergrown with quartz or with opal.
Chrysoprase
A variety of chalcedony that is apple-green in color.
Comments:
A substantial amount of material identified as chalcocite may actually be djurleite (Cu31S16), as they are very commonly intergrown.
Inaccurate data? Better photos? .
Dumortierite (Aluminum Boro-silicate Hydroxide) is a blue to violet silicate mineral that is used as an ornamental stone (and sometimes as a semi-precious stone in jewelry). Dumortierite quartz is a massive variety of opaque quartz that is intergrown ...
Twinning (Crystal) (n) Two or more intergrown crystals, formed in a symmetrical arrangement.
Uniaxial Gemstones (a, n) In uniaxial stones, the optic axis is parallel to the c-axis.
 See also: Crystal, Mineral, Crystals, Quartz, Minerals
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