Unformatted text preview: a fine grained texture Phaneritic: (crystals 1-10mm) slow cooling, viscous magma, and/or good nucleation (coarse-grained) Pegmatitic: (Crystals >1cm) very slow cooling, viscous magma, and/or good nucleation (very coarse-grained) Porphyritic: (large and small crystals) slow, then rapid cooling and/ or change in magma viscosity or composition. Glassy: rapid cooling and/or very poor nucleation Vesicular: rapid cooling of gas charged lava, gas bubbles in lava Pyroclastic: accumulations of rocky materials that have been fragmented and ejected by explosive volcanic eruptions...
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- Summer '08
- Granite, Basalt, rapid cooling