Regular coin types that changed colour

[<k>]

Nickel-brass, as in our member krishna's example on the previous page, is probably less expensive than copper-nickel.

The quest over the years has been to use less expensive but durable metals, since copper, for instance, has become more expensive because of diminishing returns in mining. In other words, the low-hanging fruit has already been picked, so far as metal ore is concerned. Now there is increasing use of plated steel in order to reduce costs.

The other aspect is that sometimes a change of colour is indeed specifically required. The more visible differences that there are between coin types, the easier it is to tell them apart.

[Henk]

Switzerland, 5 rappen.

From 1981 the 5 rappen coin was minted in aluminium-bronze instead of copper-nickel.

Presumably this was intended to differentiate it from the 10 and 20 rappen coins with their similar designs.

More likely to differentiate it from the 1/2 Franc coin.
5 rappen copper-nickel: 17,15 mm and 2 grams
1/2 franc copper-nickel: 18,2 mm and 2,2 grams

There also is a brass version of this coin, issued in 1918: https://en.numista.com/catalogue/pieces169.html
Likewise there are also brass versions of the 10 and 20 rappen

[<k>]

There also is a brass version of this coin, issued in 1918.
Likewise there are also brass versions of the 10 and 20 rappen.

These look like brief war-time economy measures, even though Switzerland was neutral in that war.

[<k>]

Belize, 1975.  1 cent: bronze.  5 cents: nickel-brass.






From 1976 onwards, both coins were minted in aluminium.

[<k>]

South Korea, 1 won, 1966.  Brass.




South Korea, 1 won, 1969.  Aluminium.

Both coins were actually the same size.

[<k>]

Lebanon, 100 livres, 1995.  Brass.




Lebanon, 100 livres, 2003.  Nickel.

[<k>]

Liberia, half cent, 1937.  Brass.




Liberia, half cent, 1941.  Copper-nickel.

[<k>]

Luxembourg, 25 centimes

The Luxembourg 25 centimes changed metal and colour several times.

Bronze, copper-nickel, nickel-silver (an unusual alloy), and aluminium-magnesium.

[<k>]

Mozambique, 1 metical, 1982.

The brass version of the coin was issued from 1980 to 1982.



Mozambique, 1 metical, 1986.

A lighter aluminium version was issued in 1986, though the diameter of 26 mm remained unchanged.

[FosseWay]

Slovakia 50 halierov 1993-1995 (N# 3105):



and 1996-2008 (N# 2489):

[chrisild]

More likely to differentiate it from the 1/2 Franc coin.

Yes, the Swiss mint "played" with alloys back then. The 5 ct/rp coin used to be Cu-Ni, then (mostly in 1918) brass, then Cu-Ni again. Starting in 1932, it was nickel, as from 1942* Cu-Ni, and as from 1981, alu-bronze (Cu92 Al6 Ni2).

Also see the Swissmint FAQ:
(Q) When was the "golden" 5-centime coin introduced?
(A) In 1981. Prior to that it was in white cupronickel; it is in yellow aluminium bronze today. The change was made in order for it to be easier to distinguish between 5-centime coins and ½-franc coins.

(* The 1940 pieces were also Cu-Ni, but not the 1941 coins.)

[<k>]

Nicaragua, 10 centavos.

The Nicaraguan 10 centavos coin of 2002 was made of brass-plated steel.

That was a one-year type only.

The coin became aluminium from 2007 to 2015.

[<k>]

Netherlands Antilles.

From Numista.

Netherlands Antilles: the 1 cent and 2½ cent coins switched from bronze to aluminium in 1979.

[<k>]

Peru.

Peru. The 1 centimo coin changed from brass to aluminium in 2005.

Peru. The 5 centimos coin changed from brass to aluminium in 2007.

[<k>]

In the case of the Swaziland 10 cents of 2011 and 2015 that I posted earlier, I noticed afterwards that the 2015 version had also been reduced in size. I then decided not to post any others that not only changed colour but simultaneously changed size. There are quite a few that did both, including some modern coins from Paraguay with nice designs. The New Zealand 10 cents coin was reduced in size and also changed colour, so that is another well known example that I have not included here.

Incidentally, the Slovakian 50 halierov that FosseWay showed was also simultaneously reduced in size. The design on the newer coin was also sharper and more detailed. Probably I should start another topic at some point for coins that changed both colour and size simultaneously.