Johnson Matthey silver bars why I stack themJohnson Matthey Assayers & Refiners. 9999 Fine Gold Bar Argor-Heraeus (In Assay) Swiss HOLO Back Kinebar. 1 Gram Gold Royal Mint U. For sale is a Johnson Matthey Assayers & Refiners Half Troy Ounce. The seller is jm_gold_and_silver and is located in this country US.