1921 UK One Penny With Streaks

Bronze is an alloy, not an element.
The UK had issues with their bronze in 1921. We had a discussion about that within the last year or so. A search should turn something up.
Here's one of mine that I posted then (12/2025).

I am old enough to remember these pennies in circulation, and lots of early George V pennies were streaky. They were still common finds right up to Decimalization in 1971.

Thanks NumisRob - guess it's a conversation piece then

1921 was the peak year in mintage of these coins at 129.7M

ijn1944 do you know any more about the metallurgical issue? I haven't found HondoB's reference yet so maybe it was discussed there. I did find that there were striking issues with the obverse design of this coin that ultimately led them to modify the bronze alloy mix beginning with the 1923 issue. Other than that I haven't found anything. Was it a mixing issue or maybe the constituent elements were not of the correct purity that led to the streaking issues? Just curious if you know.