Science Olympiad Rocks and Minerals B Rules and Concepts

Vocabulary terms and definitions covering the official Science Olympiad Division B Rocks and Minerals event parameters, rock and mineral definitions, textural classifications, metamorphic grades, and gemstone varieties.

Mineral

A naturally occurring inorganic solid with a definite chemical composition and crystalline structure.

Rock

A naturally occurring solid mass composed of one or more minerals or mineraloid matter; it can be an aggregate of one (monomineralic) or more minerals (polymineralic), and unlike minerals, can be made of organic matter.

Monomineralic rock

A rock composed of an aggregate (mixture) of only a single mineral.

Polymineralic rock

A rock composed of an aggregate (mixture) of two or more minerals.

Polymorphs

Minerals with identical chemical compositions but different crystal structures, such as aragonite/calcite, diamond/graphite, orthoclase/microcline, and sillimanite/andalusite/kyanite.

Bowen's Reaction Series

The schematic representation of the relationship between mineral crystallization and temperature in cooling magma.

Protolith

The parent rock prior to metamorphism (e.g., shale for slate, limestone for marble, sandstone for quartzite, peridotite for serpentinite, and basalt or gabbro for amphibolite).

Index minerals

Metamorphic minerals limited to chlorite, muscovite, biotite, garnet, staurolite, kyanite, and sillimanite that indicate the grade or intensity of metamorphism.

Aphanitic

A fine-grained igneous rock texture typically formed through rapid cooling at or near the Earth's surface.

Phaneritic

A coarse-grained igneous rock texture typically formed through slow cooling beneath the Earth's surface.

Foliated metamorphic texture

A texture in metamorphic rocks characterized by planar arrangement of mineral grains or structural features, such as slaty cleavage, schistose, and banding.

Clastic texture

A sedimentary rock texture made up of discrete rock fragments or mineral grains, also described as detrital or terrigenous.

Primary sedimentary structures

Features formed during sediment deposition—including plane bedding, crossbedding, ripple marks, mud cracks, graded bedding, and fossil tracks & trails—that imply depositional processes and environments.

Mineral habit

The characteristic external shape or morphology of a crystal or aggregate, limited to forms such as acicular (needlelike), bladed, botryoidal, cubic, dendritic, dodecahedral, doubly terminated, druzy, geodic, hexagonal, hopper, massive, micaceous, octahedral, pisolitic, prismatic, radiating, rosette, stalactitic, twinning, and tabular.

Rock cycle

The geologic cycle involving melting & solidification; uplift, erosion & deposition; burial, compaction & cementation; and heat & pressure resulting in recrystallization & deformation.

Bauxite

A mineral resource and rock type explicitly classified under sedimentary rocks in the official competition parameters.

Gemstone varieties of Beryl

Precious and semi-precious gemstone varieties of beryl limited on the rules list to emerald, aquamarine, and morganite.

Gemstone varieties of Spodumene

Gemstone varieties of spodumene limited on the rules list to kunzite and hiddenite.

Gemstone varieties of Corundum

Gemstone varieties of corundum limited on the rules list to ruby and sapphire.

Gypsum varieties

Specific named varieties of gypsum including alabaster (massive), satin spar (fibrous), and selenite (crystalline).