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Figure 1b

Figure 2:

Classification of common volcanic rocks (lavas). The texture and presence of quartz and feldspar are used to determine the row. The most abundant other phenocryst types are used to determine the column.
Aphanitic texture refers to grains that are too small to see.

Porphyritic texture refers to the condition where larger grains (phenocrysts) are surrounded by much smaller grains (groundmass).

Figure from Raymond, L. A., 1984, Petrography Laboratory Manual, vol. 1: Hand specimen Petrography. Geology Services International, NC, 170 p.
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