Rights Holder: The British Museum
CC License:
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Unique ID: PAS-22BC88
Object type certainty: Probably
Workflow
status: Awaiting validation
White metal strip with geometric designs and Arabic script (including prayers evoking Allah), probably part of a celestial or astrolabe which has been cut into a strip to be used as an amulet. The object may have once been rolled (though evidence for that is unclear), but was found open.
The surface was analysed by XRF, which detected circa 73% weight copper, circa 27% weight zinc, as well as less than circa 1% weight silver, suggesting that its core is made of brass with a very thin surface plating layer of silver (i.e. it is not potential Treasure). The relative high amount of zinc in the alloy and the absence of trace elements detectable by XRF may suggest a post-medieval date.
The motifs have been achieved by fine etching (rather than by engraving) and this also reinforces the suggestion of a recent date.
Notes:
The PLA (landowner) have generously allowed this find to be donated to the British Museum.
XRF analysis and report was undertaken by Aude Mongiatti, Susan La Niece and Anthony Simpson (British Museum).
Evidence of reuse: cut from a larger item
Current location of find: British Museum
Subsequent action after recording: Donated to a museum
Broad period: POST MEDIEVAL
Date from: Circa AD 1750
Date to: Circa AD 1900
Period of reuse: POST MEDIEVAL
Quantity: 1
Length: 48 mm
Width: 6 mm
Thickness: 0.02 mm
Weight: 0.36 g
Date(s) of discovery: Saturday 30th March 2013
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Other reference: CSR analytical request no AR2013-22
Primary material: White metal
Completeness: Incomplete
Surface Treatment: White metal coated
4 Figure: TQ3878
Four figure Latitude: 51.48412374
Four figure longitude: -0.01394376
1:25K map: TQ3878
1:10K map: TQ37NE
Grid reference source: Generated from computer mapping software
Unmasked grid reference accurate to a 10 metre square.
No references cited so far.
I don't think this is part of an astrolabe but it is very interesting and could be a segment of an astrological instrument. The "high" zinc content (compared to medieval European instruments) is possible for the Islamic world in that period. The silver may well be incorporated in the matrix as a by-product of the ore rather than on the surface. Is the thickness really 0.02 mm?!