Igneous Textures

What are primary textures in rocks?

Textures that occur during crystallization and result from the interactions of the melt and crystals.

What are secondary textures in rocks?

Alterations that take place after the rock is completely solid.

What is the sequence in the formation of crystals?

Initial nucleation, subsequent crystal growth, and diffusion of chemical species.

What is nucleation in the context of crystallization?

The clustering of a critical size of compatible ions resulting in supersaturation.

What does undercooling refer to in crystallization?

The cooling of melt way below the true crystallization temperature of the mineral.

How does the structure of crystals change during crystallization?

Crystals can evolve from simpler structures to more complex structures.

What is crystal growth?

The addition of ions onto already existing crystals or crystal nuclei.

What is required for mineral growth to continue?

New material must diffuse through the melt, the depleted zone, and reach the crystal’s surface.

What is the effect of cooling rate on crystal formation?

The rate at which magma cools affects the size and arrangement of crystals, leading to various textures.

What are examples of crystal textures resulting from cooling rate?

Fine-grained, coarse-grained, or glassy textures.