The;
ZI ( minimum 925 fineness)
ZII( minimum 835 fineness) and
Z( minimum 800 fineness)
Introduced in 1953 upon the Dutch hallmarks renewal; introduction of the
Z marks for silver objects which are submitted in finished condition, which consequently could then not be assayed as thoroughly (
limited assay only) and are assayed with the touchstone; the touchstone testing method is a fast non-destructive screening and assaying method. The kind of precious metal and the fineness are determined by testing the colour and chemical resistance. The materials used are touchstones, touch acids and touch needles (alloys with an accurately established fineness of precious metal). The advantage of the touchstone testing method is that in principle every parts of the article can be tested. Sometimes in combination with X ray.
Laboratory assaying (full assay) takes longer and more expensive; in the laboratory the touchstone method for platinum, gold and silver articles will be supported by the following methods:
-potentiometric titration for silver;
- (micro) cupellation for gold;
-X-Ray Fluorescence Spectrometry (XRF) for compositions of precious metal alloys.
The Z mark could be used for imported finished object brought in by a registered importer/trader and those objects are marked; with or without a decimal fineness number & importers mark and corresponding Z mark. Today every private person (silver-collector) in Holland can visit the assay office for private testing; all objects made out of precious metals with or without (hall)marks and upon owners request the object will be marked with the correct (Z) mark but be warned fake marks could be deleted /crossed out by the assay office, make sure you first discuss your options.
And remember
limited assay, if the assayer has some doubts,
could result in a downgrade. I have seen British sterling (925); full row of British hallmarks but stamped Z II for minimum 835/1000 instead of ZI for minimum 925/1000 fineness what we should expect. Often we find decimal 925 in combination with ZII mark only.
In my opinion the marrow scoop maker’s mark MT in a de-formed frame could be 18th-19th century; British, Continental or Colonial/ American and the ZII mark is a later addition to indicate precious metal
minimum silver fineness 835 without the Z we should call it made out of white metal.
Oel.