Can't find this black star cap badge anywhere

[LaurenceU]

Hi All

First post! I've been collecting badges on and off for a few years now. Will only buy anything with a red star on but have around 40 at the moment. Thought it about time I found out a bit about them. But, one has got me stumped. Its a black enamel on gold star (I know I said I only collected red stars, this is the exception!) with hammer and sickle in gold in centre. I presume a cap badge but does not have two prongs, it has a needle fastener. Its quite nicely done, a little larger than the standard cap badges.

I've attached a really grotty pic (sorry) showing the black star alongside three other red stars I have. Does anyone have any thoughts on its origins.

Thanks for your help.

Laurence