Logo of Basel Historical Museum
Dunkle AnsichtHelle Ansicht
Crafts and Trades

Touchstone for gold assay

Key data

dated 1546

Slate, brass gilt and engraved

length with ring 33 cm

Inv. 1890.86.


The cost of gold constantly gave occasion for forgery or misstatement of the gold content of gold products. The scraping test is an old and simple method of testing gold content, and is used by goldsmiths even now. The gold to be tested is rubbed on a black slate touchstone so as to leave a mark. The colour of the mark is compared to that of needles of precisely known gold content. The assay with acid is somewhat more exact. The mark on the touchstone is dabbed with several acids calibrated against the usual gold alloys. The acid that dissolves the mark indicates the fineness of the gold alloy. For very exact measurements the fire test (which cannot here be described in detail) is used. It has, however, the major drawback that a sample must be cut out of the object, involving a considerable intrusion. The touchstone shown here is a particularly finely made goldsmith's instrument from the mid C16. The gilt brass ferrule fitted to one end of the touchstone has two unidentified escutcheons on its narrow sides. On the wide sides floral ornament and the date 1546 are engraved. The narrow sides of the stone have relief decoration.

Selection of similar objects


Basel Historical Museum
Management & administration
Steinenberg 4
PO box
CH – 4001 Basel

Reception: +41 61 205 86 00

Sign up for our newsletter
Logo: FacebookLogo: InstagramLogo: TwitterLogo: YouTube
Logo: Culture inclusive
Open today from 10 AM to 5 PM
Open today from 11 AM to 5 PM
Open today from 11 AM to 5 PM
Tuesday to Sunday 10 AM to 5 PM
Wednesday to Sunday 11 AM to 5 PM
Wednesday to Sunday 11 AM to 5 PM