Silver tarnishes due to a chemical reaction that naturally occurs when the silver is exposed to moisture and chemicals in the air. When the atoms of silver come into contact with oxygen, a film of silver sulphide forms on the coin surface, with the underlying layers not being affected.
Sometime, during AD 150-152 in the
North Eastern corner of the
Roman province of
Britannia, a citizen was compelled to bury
his hoard of 522 silver
denarii, equivalent in value to around $14,516 approximately in modern day currency. A substantial amount given that a
Roman soldier would have been paid around 300
denarii per year. The silver
denarii stretched from the coins of
Mark Antony (32-31 BC) to
Faustina II (AD 152), some 184 years of
Roman history. All
bar the early
Legionary issues were struck in
Rome. The Ropsley
Hoard was found by a metal detectorist in March 2018, who was carefully searching a large
field in Lincolnshire, not far from the
Roman town of Ancaster and Ermine Street, the
Roman road connecting
London to Lindum
Colonia (
Lincoln) and
Eboracum (York).
When these coins were removed from the ground, there were extensive green corrosion products meaning they were not legible. Once at the British Museum, the coins were conserved in order that they could be counted and identified during which fragments of charcoal were recovered and identified as being from a willow tree by the department of scientific research. How this burned
wood came to be buried with these coins is a mystery, perhaps the coins were being counted by their owner close to a spitting fire before their final concealment or perhaps even a charcoal pencil was used to keep a tally of exactly how many coins were being hidden! Further
work by specialist conservators to remove the encrustation, but not damage the coins themselves, took place over a number of months.
Hadrian (11 Aug 117 - 10 Jul 138 AD), Silver Denarius, Ropsley Hoard 21, RIC II 234d, RSC II 615, BMCRE III 608, Strack II 231, Hunter II -, SRCV I -, EF, excellent portrait, well-centred and sharply struck on a tight flan, lightly toned, little wear, some hoard encrustations both sides, edge cracks, weight 3.27g, maximum diameter 18.0mm, die axis 200°, Rome mint, 134-8 AD; obverse HADRIANVS-AVG COS III P P, laureate head right; reverse FELICI-T-AS AVG (Happiness of the Emperor), Felicitas, draped, standing half-left, caduceus in right hand, olive branch in left.