All British Sovereign and Half-Sovereign coins produced from 1817 to present are 22 carat gold.
There were 14,000 1973 Isle of Man gold "uncirculated" Half-Sovereigns minted. There were 1,250 1973 Isle of Man "Proof" gold Half-Sovereigns minted.
Isle of Man Sovereigns and Half-Sovereigns are very similar, but not exactly identical to British Sovereigns and Half-Sovereigns. The Isle of Man Sovereign is 22.5mm in diameter and the Half-Sovereign is 19.5mm in diameter.
All British Sovereign and Half-Sovereign coins produced from 1817 to present are 22 carat gold.
Pictures of a specific coin are difficult to come by. Frequently you should be able to find one on eBay, but the picture is withdrawn after the coin is sold. All British Sovereigns from 1893 to 1901 inclusive are pretty much identical except for the year. Sovereigns are near identical to Half-Sovereigns from the same period, Half-Sovereigns being a few millimetres smaller in diameter. See the link below for an 1894 British Half-Sovereign.
The fact that they were found in 1962 does help identify them. Presumably they are British, what year is inscribed on the coins?
Your coin is either a Sovereign (22.05mm) or a Half-Sovereign (19.3mm). All Sovereigns and Half-Sovereign coins are made from 22 carat gold.
Sovereigns and Half-Sovereigns minted in Australia at the Melbourne, Perth and Sydney Mints, were in fact British coins and were struck to the same dimensions, specifications and design as the coins would have been had they been minted at the Royal Mint in London. The exception to this is the Sovereigns and Half-Sovereigns minted at the Sydney Mint between 1855 and 1870 which had "Sydney Mint" and "Australia" inscribed on the reverse, which were for the use of the Colonies. Since 1816, all Half-Sovereigns were 0.917 fine gold, weighed 3.994 grams (half of the weight of a Sovereign) and 19mm in diameter.
British decimal Half-Sovereigns are minted annually in most years as a non-circulating Proof FDC gold bullion coin. The last pre-decimal Half-Sovereign minted was issued in 1937 as a non-circulating Proof FDC coin.
Die numbers were only on Sovereigns and Half-Sovereigns minted by the Royal Mint. Sovereigns and Half-Sovereigns minted at mints other than the Royal Mint, will have a small mintmark on the reverse of the coin near the date.
There were no British Half-Sovereigns minted from 1938 to 1979 inclusive.
No. Any 1898 Half-Sovereigns not minted at the Royal Mint London, were minted at the Royal Mints in Melbourne, Perth and Sydney. All Half-Sovereigns minted for any year in Canada, were minted at the Royal Canadian Mint in Ottawa.
A sovereign contains roughly 0.2388 troy ounces of gold. At the current gold price, £1092.40 per troy ounce, you are looking at a value of around £260. Most gold sovereigns sell for around that on ebay. A half sovereign is obviously worth half of that: £130. If you mean purchasing power, I can't be sure but I believe a half sovereign would be the equivalent of around £75 by today's standards. I was looking myself for information on the purchasing power specifically, but the closest approximation I can find compares the value of a 1895 sovereign to £150 in 2007. I don't think it would have changed much.