1920's-30's Deco Marcasite Brooch

[CuriousJoeC]

If anyone can identify the marks on this brooch I'd be very appreciative. I would think from the design that it's c. 1930. Also, I've never seen this stone before and I'd like to know what it is ...the bottom of the stone looks like it was dyed blue.
Thanks a lot, Joe

[JLDoggett]

The stone appears to be jasper, I can not explain the blue underneath the stone. Stylize it appears to be from the mid-20's and northern Europian manufacture, though I am sure someone will chime in with a decyphering of the marks.

[admin]

The marks appear to be German, but the image is too small for a positive ID.

[CuriousJoeC]

I just found marks that seem to be a variations of the marks on my brooch for the German firm of Martin Mayer founded in 1888 in Mainz

[admin]

I do not think this is a Martin Mayer product.
Regards, Tom