Silicate Minerals and Igneous Processes

These flashcards cover key vocabulary related to silicate minerals, their structures, properties, and igneous processes, essential for understanding their roles in geology.

Tetrahedra

A geometric shape with four faces, commonly used to describe the structure of silicate minerals where silicon ions are at the center.

Orthosilicates

Silicate minerals with isolated tetrahedra, having a Si:O ratio of 1:4.

Disilicates

Silicates where two tetrahedra share one oxygen, characterized by a Si:O ratio of 2:7.

Ring Silicates

Silicates that consist of tetrahedra arranged in a ring structure.

Single Chains

Silicates with chains of tetrahedra linked by sharing two oxygens, exhibiting specific physical properties.

Double Chains

Silicates consisting of two chains of tetrahedra linked through shared oxygens, which form octahedral sites.

Sheet Silicates

Silicates where tetrahedra are arranged in sheets, with significant cleavage properties.

Framework Silicates

Silicates with a three-dimensional network of tetrahedra, allowing for complex crystal structures.

Birefringence

A property of minerals that describes how they refract light, indicated by order levels (1st, 2nd, 3rd).

Cleavage

The tendency of a mineral to break along specific planes of weakness, resulting in flat surfaces.

Twinning

The growth of two or more separate crystals of the same mineral in a symmetrical configuration.

Zoning

The variation of chemical composition in a single crystal from its core to its rim, indicating environmental changes.

Volatiles

Gases dissolved in magma, such as H2O and CO2, that significantly influence eruptive behavior.

Solidus

The temperature at which a solid begins to melt and form a liquid as temperature increases.

Liquidus

The temperature at which all components of a solid melt completely into liquid.