Identify the rock that is not sedimentary from the following list commonly encountered in construction materials. Choose the odd one based on geologic origin.

Introduction / Context:Construction aggregates and stones are classified by geologic origin: igneous, sedimentary, or metamorphic. Recognizing the origin helps anticipate durability, strength, and weathering behavior. This question asks for the non-sedimentary rock among common building materials.

Given Data / Assumptions:

• Gravel, sandstone, gypsum, and lignite typically form via sedimentary processes.
• Dolerite (also called diabase) is an igneous rock.
• We select by origin, not by end-use properties alone.

Concept / Approach:Sedimentary rocks form from deposition (clastic like sandstone and gravel) or chemical/biochemical precipitation (gypsum, lignite as a coal). Igneous rocks crystallize from magma or lava; dolerite is a medium-grained mafic intrusive/extrusive equivalent to basalt, thus non-sedimentary.

Step-by-Step Solution:

Verification / Alternative check:Geology references consistently define dolerite/diabase as igneous, compositionally akin to basalt and gabbro, not a sedimentary rock.

Why Other Options Are Wrong:

• Gravel/Sandstone/Gypsum/Lignite: all sedimentary in origin; selecting any would contradict their formation processes.

Common Pitfalls:Confusing sedimentary gypsum with metamorphic anhydrite; assuming lignite is metamorphic because coal ranks vary—lignite is a low-rank sedimentary coal.

Final Answer:Dolerite