Silver Ingot hallmark identification

[Alex944]

Hi Folks,

I picked this up today and was wondering if anyone could help clarify the sovereign mark on this Ingot. 
 

from what I have found so far about the marks:

maker: GMC (dont know much more)

assay office: Birmingham

country: England/UK

Date letter (C) - 1977

 

however, the sovereign effigy (I assume its Elizabeth) is not one I could fine on reference. Would anyone know if its a standard mark or commemorative  mark?

thanks for your help!

[Roy]

1977 (C) is the Silver Jubilee Year.

The effigy was a one-off.

 

edit: it's sterling silver.

Edited August 19, 2023 by Roy

[sixgun]

It's the Birmingham Assay Office hallmark.

[stefffana]

Hi, Alex.

What you discovered yourself is true. Also, what @Roy and @sixgun said is accurate.

I have tried to find more informations about the maker GMC from Birmingham. The maker mark GMC in a shield can not be associated with any known (documented) silversmith from Birmingham. 

There are only two factories with these initials, but both of them were active in the first half of the 20th century and also their stamp was different, having another shape:

1. Gorham Manufacturing Corporation, the american well known brand who had a branch in Birmingham.

2. G. Mills & Co. They probably closed their factory during the second world war; their mark was not seen since.

So, I really don't know who made your ingot, but I have seen an abundance of unknown silver makers marks associated with the Silver Jubilee year 1977, not only on ingot pendants, but on spoons, plates, miniatures, etc. Maybe a lot of artisans/hobbyist seen an opportunity to sell small memorabilia silver products only that year then stopped.

[Alex944]

Thank you all for your input, I do very much appreciate it!