For a couple of years, Britain’s Pobjoy Mint has been issuing numerous colored coins struck in titanium. The blanks used for the coins have anodized. This is an electrochemical process that produces an oxide layer on the surface of the titanium.
When light reflects from the anodized surface, the thickness of the oxide layer affects the color we see. That color is stable. It will not fade, discolor or change.
Pobjoy has produced a range of differently colored, 36.10 mm, 10 g titanium £2 coins featuring the wildlife of various countries for which the mint makes coins. Each issue had a mintage of 7,500.
In mid-January, two such coins were struck for the British Indian Ocean Territory (BIOT). One celebrated the Manta Ray (Manta birostris); the other, the Coconut Crab (Birgus latro). The former coin was blue; the latter, brown.
It was then the turn of British Antarctic Territory, whose grayish-blue coin shows a Blue Petrel (Halobaena caerulea). South Georgia and the South Sandwich Islands came in March with an “ice grey” £2 showing the Leopard Seal (Hydrurga leptonyx). See www.pobjoy.com.
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