12 yrs ago I actually paid FORTY DOLLARS each for several picture frames for flint...
The very same type frames can be had at thrift stores for around three $
No matter what, your going the have to discard the glass and create a strong ( and original ) backing.
Your doing a good project..handcrafted originals really enhance artifacts .. AND the sky's the limit for originality..check the "flint tree mosaic " under the FredB show posting.
I think you would have gotten 10 or 15 more replies to your posting but most people thought you were referring to framing a piece of mosaic from a Roman bathhouse floor. tee hee
I looked closer at the projects..The top 3 the maker incorporated a glass front, must have made a slightly deeper back board / box... ( I dont care for the effect )
The dark frame around the white eagle apeares to be EXACTLY the same COLOR & design as my $40. one.
Last project uses liquid nail for the glue. Hot glue might be a better choice for some designs. ( Hot Glue is instant dry,,,Liq nail takes DAYS to cure )
Eric..In case you missed it in that off topic section here before you get to the regular forum page ( I dont know what the section is called, it the one nobody ever looks at )...
Has a close look of how the flint trees were made ( also on his website inder "DISPLAYS " )