Albert Barnes Commentary Jeremiah 10:9

"There is silver beaten into plates, which is brought from Tarshish, and gold from Uphaz, the work of the artificer and of the hands of the goldsmith; blue and purple for their clothing; they are all the work of skilful men." — Jeremiah 10:9 (ASV)

Or, “It is a piece of wood (Jeremiah 10:8 note); indeed, beaten silver it is, which is brought from Tarshish, and gold from Uphaz: it is the work, and so on.”

Tarshish ... Uphaz - See the marginal reference and (Genesis 10:4). Possibly Uphaz was a place in the neighborhood of the River Hyphasis.

Blue and purple - Both colors were purple, from dyes obtained from shellfish: but the former had a violet, the latter a red tinge.