Hallmark help old 18K ring

[Fax]

Long time reader here.
I have acquired an old 18K ring with a hallmark where I have gone lost... and need your expert help.

Just loved the colour combination and low profile

Ring hallmarks I can see 18K, Eagle head and C4?? or might it be something else? It also looks like some hallmark are missing due to old resizing.

I am especially curious in regards to origin and if possible a more precis age. Even though you should never ask a lady for age, do I assume that she is around 150 years old, give or take.

Stones has been examined by a trusted gemologist.
There are two old cut diamonds.
Natural emerald and blue sapphire, treatment unknown, but most likely not heated.
The pink sapphire (bought as ruby) has some blue flashes but it looks like the flashes comes from natural inclusions.

Thank you for any help in advance

 

[Ally T]

Beautiful ring

Calling @YadaYadaYada the super sleuth of old hallmarks!

 

[YadaYadaYada]

Thanks @Ally T that is really sweet to say.

I didn’t find any maker’s marks that matched this but French jewelry can have an eagle mark although I think on rings it’s usually on the outside of the band.

Passing the baton to @stracci2000 to see if she has any ideas here.

Beautiful ring, love the colors!

 

[Fax]

Thank you so much for your kind words and help @Ally T and @YadaYadaYada. It was love at first sight, phu this is a slippery slope

I am wondering if it might be a Swedish year stamp? C4=1831 or G4=1834, but it is missing the characteristic "cat foot" (hallmark for Swedish gold and silver).

 

[Daisys and Diamonds]

what a beautiful ring

 

[stracci2000]

It definitely looks like the French eagle, but why is it left facing?
The other marks are hard to make out, too. Typical teeny jeweler's marks that make you crazy!
This one is mysterious!

 

[Fax]

Thank you @Daisys and Diamonds and @stracci2000

It sure is a mystery I am more than impressed of anyone seeing anything, on what seems like a forgotten language, in micro writing.
The hallmark to the left is a weirdly shaped 18K stamp that can be seen, but harder to photograph. I will try to take a better picture tomorrow.

 

[Dreamer_D]

Can you try taking a picture though a loupe?

 

[Fax]

That was not easy... I will bring out the good camera and se what I can do. This is what I managed so far (unfortunately did not manage with the loupe).