Placer (noun)

1. A deposit of gravel or sand containing valuable minerals, such as gold or platinum, that can be mined by washing or dredging.
2. A mining deposit of gravel or sand containing valuable minerals, typically found in stream beds or river banks.

Origin:

The word placer comes from the spanish word placer, meaning a place where gold or other valuable minerals are found. it refers to a deposit of gravel or sand containing valuable minerals, such as gold or platinum, that can be mined by washing or dredging.

Examples:

1. The placer was rich in gold and other precious metals.
2. The gold rush was sparked by the discovery of a placer in California.
3. The placer mining was done by washing the gravel to extract the gold.
4. The placer deposit was found in a stream bed.
5. The placer mining was done using a dredge to mine the river bed.