myrmekitic

myrmekitic

[¦mər·mə¦kid·ik]
(petrology)
Pertaining to the texture of an igneous rock marked by intergrowths of feldspar and vermicular quartz.
Having characteristic properties of myrmekite.
References in periodicals archive ?
Textural study shows that some of the plagioclase is formed by transformation of orthoclase along with wormlike intergrowth of quartz, giving rise to myrmekitic texture.
An intergranular albite-rich (in some cases, myrmekitic) plagioclase film commonly develops between the plagioclase and K-feldspar crystals.
Perthitic and myrmekitic intergrowths are observed in few sections.
The mineralogy is 40% plagioclase (3% of which is myrmekitic), 29% quartz, 28% potassium feldspar (microcline and orthoclase), 3% biotite, with trace magnetite and rare epidote and chlorite.
The tonalite unit, between the gabbro and volcanic rocks, has strained quartz and myrmekitic feldspars.
In addition to the metamorphic (mainly hexagonal) pyrrhotite of the older stratiform pyrite-pyrrhotite deposit, the mineral also occurs as aggregates to 3 mm of microscopic ([greater than or equal to]0.1 mm) grains and columnar crystals or myrmekitic pyrrhotite-gudmundite intergrowths (Cambel, 1959).
Some of the rocks contain graphic and myrmekitic intergrowths of quartz and feldspar.
Myrmekitic intergrowths of johnsomervilleite with quartz and feldspar are associated with cyrilovite, jahnsite and phosphosiderite.