A poikiloblast is a
porphyroblast
A porphyroblast is a large mineral crystal in a metamorphic rock which has grown within the finer grained matrix. Porphyroblasts are commonly euhedral crystals, but can also be partly to completely irregular in shape.
The most common porphyrobl ...
mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ( ...
with small
inclusions of the previous rock in it. From the texture (if any) shown in the inclusion, the deformation history of the rock can be interpreted, as the inclusions are always older than the porphyroblast.
Petrology
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