I am new to this Forum, but of course I've done my personal research before asking my question.
In my research I found that brooch shape & engraved pattern and c-clasp alongside with t-pin indicate that the brooch may be dated early 1900s (around 1900-1920). On the other hand makers mark is complete mystery for me and it doesn't look close to chinese export marks i've found on internet. I've added little image of brooch pattern (in green frame) in case if it can help. Hope this does not violate Forum rules.
I would appreciate any help with identifying of the makers mark.This is really my last hope.
Many thanks for looking this topic.