poikilitic


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Related to poikilitic: ophitic, trachytic, poikiloblastic

poikilitic

[‚pȯi·kə′lid·ik]
(petrology)
Of the texture of an igneous rock, having small crystals of one mineral randomly scattered without common orientation in larger crystals of another mineral.
References in periodicals archive ?
At Burnt Point, massive, pegmatitic gabbro contains cumulus ortho- and clinopyroxene, and large poikilitic post-cumulus amphibole and plagioclase.
The Talavera sample shows large anhedral poikilitic orthopyroxene crystals, leading to a hypidiomorphic subophitic to ophitic texture.
In some thin sections the hornblende is poikilitic and contains inclusions of quartz.
Las Minas Monzodiorite and the Ibague Batholith presents Augite (Figure 3b) as an accessory with less than 2% and commonly enclosed into biotite crystals (Figure 3c) forming poikilitic textures (Figure 3d).
3) Quartz occurs as cloudy anhedral grains with characteristic weak birefringence, prominent undulose extinction and low relief while muscovite occurs as tiny elongate plates with poikilitic crystals of quartz.
Occurrence: As a monomineralic veinlet cross-cutting poikilitic nepheline syenite.
5a), locally reaching 20 cm, and they sometimes have ragged poikilitic margins containing uniformly distributed inclusions of matrix minerals.
Finally, there are some rare but interesting boulders consisting of coarse-grained diorite with poikilitic megacrysts of amphibole that grew around leucocratic droplets (Fig.
The pyroxene is intergranular to subophitic, but in some rocks grains of other minerals may be poikilitic in habit.
Large, poikilitic hornblende crystals are believed to have formed after this magma (and entrained mafic minerals) was injected into a shallower water-rich environment near the roof of the Greendale Complex.
General appearance: Fine, short prismatic grains (up to 1 mm ) and coarse poikilitic grains (1.