silt, predominantly quartz mineral particles that are between sand size and clay size, i.e., between 1/16 and 1/256 mm (1/406 –1/6502 in.) in diameter. Silt, like clay and sand, is a product of the weathering and decomposition of preexisting rock. Hardened silt forms a sedimentary rock called siltstone, which tends to deposit in thin layers sometimes referred to as flagstone because it is hard, durable, and flat, breaking into nearly rectangular slabs.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.
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