Technical notes
Short answers to the questions behind a gold biscuit.
01
Read fineness correctly
999.9 denotes 999.9 parts gold per 1,000 by mass: 99.99%, or four nines. 999.0 is 99.9%, or three nines. These describe a specification; the assay establishes the fineness of the material tested.
22 carat is 22/24 gold, approximately 916.7 parts per thousand. It is not exclusive to jewellery: investment bars and coins can also have lower fineness than 999.9.
02
A mark and its issuer
Read the maker’s identity, weight, fineness and any official assay mark separately. A word such as “hallmark”, an Arabic inscription or a shield illustration is not enough: identify the responsible authority and its record.
Bahrain: assay & hallmarking ↗03
Cast, minted and vacuum-cast
In casting, molten metal takes shape in a mould. Pressing or minting forms a prepared blank using dies. Vacuum casting describes casting under reduced pressure; it does not itself establish purity. The supplied portfolio combines a vacuum-cast blank with a later deep-press step.
Process ↗04
Handling and storage
Keep each biscuit protected from contact with other metal objects. Handle by the edges with clean gloves, avoid abrasive cleaning and retain its packaging and documents. Ask the supplier about any cleaning or storage requirements attached to the actual packaging.