Someone reported that the closest one to DLR is at Sea World.
There is a Mie Jewelry pick a pearl at Redondo Beach Pier. Not sure about Sta Monica Pier, but Redondo Beach would be closer if someone wants to get a pearl, and there are nice restaurants there, too.
https://miepearljewelry.com/
https://www.yelp.com/biz/mie-pearl-redondo-beach-2