New Zealand Gold Prospecting & Metal Detecting Forums Archive

Today I dug an old silver ring from North Hagley. It would have been around 8-9 inches deep. It appears to be extremely old but I cannot date it as it is not hallmarked. Normally when a silver coin is dug from this depth, it's usually in pretty-much the same condition it was dropped in. This ring however, shows obvious signs of silver degradation on the inner wall and around the rim.

My question is, would this degradation be an indication of the age of this silver?

I'm picking that this ring could well be early 1800's.........possibly even late 1700's manufacture. .....or even earlier than that???

Any ideas or clues welcomed that might either support or debunk this theory.

Edited by user Saturday, 6 July 2013 11:07:28 PM(UTC)  | Reason: Not specified

Could it be one of those rings made from a coin?

hi mate looks like the ring is silver plated and the inner metal has degraded faster than the silver plate ? looks old tho cool find ::)

Your ring looks as though it is silver plated and the plating is peeling off.

I note the comments re the silver in the ground. There are three factors to take into account;-
1) - The purity. The purity of the silver from two perspectives, one being the actual silver content eg .925 etc and the second being poor grade alloy with impurities. The latter will not occur in professionally made pieces.
2) - The soil type. Two identical coins or rings might be lost on the same day but one in neutral or alkaline soil and one in highly acidic or salty soil. The ring lost in the latter soil type will corrode while the first one doesnt.
3) - Dampness. This factor can make corrosion more rapid so that two identical rings lost in the same soil, one damp site and one wet site will degrade at different rates, the ring or coin in the damp soil will degrade far more rapidly.

Aninteresting point that I noted now and again especially in conditions where there were trees and humus was to find a coin which was noticeably corroded, tarnished or stained on the top side and yet perfect on the side facing downward. I assumed this was the combined affect of a more effective seal against the soil on the downside and lighter compact soil on the topside and the fact that more water during rain would come into contact with the top side but this is just a 'sort of Intelligent' guess'

How much does it weigh, exactly?

Interesting. Close in weight to a sixpence. I wonder how accurate your scales are.

And let's not forget sulphur!

Surprisingly I don't think Sulpfur has much of an effect out of the laboratory. Being in Rotorua I dig in a lot of sulpfur enriched areas, including soil and hot pools and streams. Most of the corroded finds have come from stream and lake beds that have a lot of movement and the item gets worn more then corroded. Example is this morning I dug a large silver ring from under the Kerosene creek waterfall (hot and highly mineralised & sulpfuric water)- it was completely covered with a hard brown coating (I thought it was a junk ring at first) but after zapping came up fairly clean. Our modern steel cored coins get dissolved into nothing in this water.

To me Oxygen level has the greatest impact. The best preserved coins I have ever found came from very liquid smelly anaerobic mud - they looked brand new including pennies. The oxygen level of course is directly related to the amount of dampness that Lammerlaw mentioned as well.

Edited by user Tuesday, 9 July 2013 7:45:11 PM(UTC)  | Reason: Not specified