These modern medals were, of course, struck in 1977 to celebrate Queen Elizabeth II's 25th reigning year. It's looks sort of silvery, but doesn't quite have the right shine in the pictures I can find. Some sources give the composition as 'white metal'. This usually means some non-precious base metal such as steel.
They were issued by the pharmacy chain 'Boots UK', at the time under the company name 'Boots the Chemist'. The design is quite pleasing and the medals are large and heavy, at 38 millimeters in diameter and around 30 grams.
worn: $1 US dollar approximate catalog value
average circulated: $3
well preserved: $5
fully uncirculated: $15
These medals were produced without any loops, hoops or clasps. Any medal with such jewelry damage, or any other kind of damage, is worth a couple dollars at most if beautiful, zero if unappealing.
Please see our Important Terminology page to properly interpret the catalog values listed above.