Paydirt.co.nz

New Zealand Gold Prospecting & Metal Detecting Forums Archive

 

The forum has moved to community.paydirt.co.nz, see you there!

This forum is now an archive to preserve the knowledge and finds posted here.

Copper coin condition
oroplata  
Posted : Friday, 18 November 2011 3:03:12 PM(UTC)
oroplata

Rank: Gold Ingot

Groups: Registered, Moderators
Joined: 16/06/2011(UTC)
Posts: 1,040
Location: Christchurch

Thanks: 23 times
Was thanked: 211 time(s) in 152 post(s)

I always wondered why the british pennies came out of the ground in much better condition than the later NZ ones.

Quoting http://en.wikipedia.org/...ry_of_the_British_penny_(1714–1901)

"Between 1839 and 1860, the penny was made of 18.8 grams of copper and was 34 millimetres in diameter. From 1860 onwards, bronze (an alloy of 95% copper, 4% tin, and 1% zinc) was used instead — the bronze penny weighed ⅓ oz (9.4 grams) and was 31 millimetres in diameter."

http://www.teara.govt.nz...6/coinage-and-currency/1 says the NZ pennies were also bronze but 97% copper, 0.5% tin and 2.5% zinc - maybe that extra zinc is what causes the problem?

http://www.teara.govt.nz...6/coinage-and-currency/2 also an interesting read.
Back to top
WWW