From 1817 until 1919, all British silver coins had a fineness of .925; i.e. 92.5% silver or sterling silver.
In 1920 the silver content was reduced to 50%.
In 1947, what were silver coins, were subsequently made from a copper/nickel alloy - no silver at all.
No circulating British coin has contained any silver since 1946.
There was no British 1888 Five Pound coin minted. The Five Pound coin with the Jubilee portrait of the Queen was only minted for Queen Victoria's Golden Jubilee year of 1887. During her reign the only other dates, with different designs, were 1839 and 1893. A number of forgeries dated 1888 are known.
There were no 1888-CC Morgam silver dollars minted.
Silver Burdett was created in 1888.
Otto of the Silver Hand was created in 1888.
British Journal of Dermatology was created in 1888.
26.730 grams is the weight standard for all US silver dollars from 1840 to1935.
It is not difficult to find one.
The weight standard for all Morgan dollars is 26.73 grams
Lowest value would be $15.00 just for the silver.
It's 90% silver with 10% copper. The coin's total weight is 26.73 grams.
All 1888 US silver coins carried a picture of Miss Liberty. Please post a new question with the coin's denomination.
1888 makes it a Morgan silver dollar, which has a weight of 26.73 grams and a diameter of 38.1 mm. A heavily worn specimen might weigh slightly less.