You searched for: “eluvial placer
eluvial placer (s) (noun), eluvial placers (pl)
A mineral deposit concentrated near a decomposed outcrop of the source and deposited by rain wash, rather than by stream action: Tom, the geologist, determined that the eluvial placer had an accumulation of valuable minerals that were formed by a gravity separation during the sedimentary processes of precipitation.

When there are eluvial placers full of heavy minerals, they become concentrated in streams, beaches, and residual gravels, and form placer deposits that include gold, platinum, cassiterite (source of tin), magnetite (ore of iron), chromite (chromium ore), ilmenite (source of titanium), rutile (another source of titanium), native copper, zircon (bluish-white gems), monazite (rare-earth elements), and various kinds of gemstones.

This entry is located in the following unit: luto-, lut-, luv-, lu- (page 4)