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Earth Materials
Minerals | Rocks

Out of Solution
Sand Crystals

Sand crystals are interesting examples of concretions where clusters of baryte or calcite crystals precipitate from groundwater to form as cement in unconsolidated sand. During their crystallization they incorporate the sand grains into their distinctive crystal structure. Therefore the majority of the pieces are actually made of quartz sand held in place by the mineral framework. Sand crystals usually form by evaporation in arid, sandy environments.

Groundwater and spring deposits