Mineral Forming Environments

• Exhibition Text

  • Minerals are not the products of accidental events in Earth’s remote geologic past but are formed in an orderly way that depends chiefly on physical and chemical conditions in their environments of formation.

    Audio Transcript
    Welcome to the area in which minerals are displayed in terms of the environments in which they are formed. Minerals are not the products of accidental events in Earth's remote and distant geological past. Rather, minerals are formed through a complex interaction of many kinds of chemical and physical processes.

    And in this series of exhibits, the various mineral-forming environments will be introduced to you. Minerals typically developed in each of these environments are arranged in groups of several individual cases.

    Minerals form either deep within the Earth, or at relatively shallow depths, or even at the Earth's surface.

    Minerals that form at considerable depths within Earth's crust do so in a (1) metamorphic environment, (2) magnetic environment, (3) pegmatitic environment, and (4) hydrothermal environment.

    Other kinds of minerals developed at or near the surface of the earth. These minerals could form in a, (1) environment of oxidation and secondary enrichment, or (2) the evaporite environment, or (3) the volcanic environment, or (4) the sedimentary environment.

    The processes occurring in these environments often relate to one another, so that certain minerals formed in one environment are basic to the development of other minerals at a later stage.

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In This Section

Metamorphic Environment

High temperature and/or pressure conditions within Earth’s crust alter the crystalline (atomic) structures of minerals without involving a liquid, or magma, phase. 

Magmatic Environment

High temperature and pressure conditions within Earth’s crust provide for minerals to develop when molten, silicate-rich liquids (magma) harden, or crystallize, upon cooling.

Pegmatite Environment

Mineral materials (elements), once widely distributed throughout the original magma, sometimes become greatly concentrated in the residual liquid at a late stage in the cooling magma.

Hydrothermal Environment

A hot, fluid residue, usually of magmatic origin, that is chiefly water contains a rich supply of metallic elements.

Hydrothermal and Metamorphic Environment

The development of a mineral deposit may involve more than one kind of environmental condition. 

Evaporite Environment

In warm and arid climates, water evaporating from landlocked, or playa, lakes may result in the development of various minerals.

Volcanic Environment

When molten, silicate-rich fluids erupt onto the Earth’s surface, minerals often form in the numerous pockets and holes that develop in the cooling lava. 

Sedimentary Environment

Dislodged by the action of water and wind, surface rock and mineral materials are transported and deposited at new sites. These sediments often change chemically in the water to allow for a variety of new minerals to develop.