Everyone in the jewellery industry knows about the 4 Cs as criteria for grading diamonds. Understandably, far fewer people know about the 5 Ps which Edinburgh Assay Office uses to assess the quality of a hallmark.
Perfect – The hallmark should be clearly legible
A hallmark should be clearly and evenly applied with all of the mark’s detail legible. For smaller marks it may require the use of magnification to read. Under 10X magnification it should be clearly readable with no doubling or blurring of the mark. All parts of the mark should be complete. Laser marks should be clean with no traces of burn.
Positioned – It should be well placed on the item
The hallmark should be in a good position on the jewellery and should look like it belongs there. It should run parallel to lines of the jewellery and appear centred. The mark should avoid the sizing area on a ring.
Precise – A hallmark’s position should be consistent across multiple items
Good set up and methodical practice for hand, machine and laser marking should produce excellent repeatability in the position and depth of the hallmark on a range of identical articles. The marks should be in the same place every time.
Protected – Application of a hallmark should not damage the item in any way
For unfinished articles where polishing has yet to take place, the tools used to support the item during hallmarking should minimise distortion or permanent loss of form, leaving a minimum of refinishing. On finished items the marking process should leave no trace of distortion of bruising on the opposite side even when applied with a punch. Finished items should not be scratched or scuffed when being handled for marking.
Permanent – A hallmark should survive what might come afterwards
If a product is unfinished and requires polishing afterwards, the hallmark should be deep enough to be capable of withstanding the finishing process leaving a permanent and enduring hallmark. If the item is finished the hallmark should be deep enough to survive the everyday wear of the item across its life span. For finished rings the mark should be capable of withstanding the ring sizing process.
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