sand

silica

desert (barren area)

to consist of; to be made up of

to be achieved; to be completed / to become; to change into / (impersonal) to reach a time; to get to a timepoint / to reach an amount/quantity / (with negative) to be acceptable; to be tolerable

Used when giving an example, without the implication that it might be the best or the only option / ... or ...

silica gel

mainly, primarily

sand

sand