Intarsia is the art of making a gem stone or a picture using slices of stone. The stones are cut so they line up against each other with no gaps. This is not the same as mosaics where the pieces of stone are separated by grout lines. Intarsia is also different from channel inlay. In channel inlay, the stones are separated by strips of metal.
Intarsia Earrings
Stones are shaped using some sort of flat lap type machine/grinder to get precise, clean edges. Stones are cut starting with the center stone, and working your way out. The piece is usually finished with a beveled edge. Intarsia is a great way to use small bits and pieces of stones that might go to waste otherwise. For detailed instructions on how to create instarsia, check this 2-part youtube series:
https://youtu.be/eddivmnCwkE
https://youtu.be/C2zuZGNW-UY
Here is an overview of the intarsia process:
1) Create a design
2) Find appropriate stones to execute the design. Using stones of similar hardness helps when it is time to polish the piece.
3) Rough out the required shapes with a trim saw
4) Refine the rough shapes with a lap/grinder
5) Clean the edges of the stones to be glued with rubbing alcohol. Glue the edges of the stones together with no gaps between them using super glue, working from the center outwards.
6) Grind the ends of the stones so they are perfectly flush
7) Repeat Steps 5 & 6 until all the pieces have been assembled
8) Clean the back of the glued intarsia piece and a THIN slab base with rubbing alcohol. Use 2-part epoxy to glue the intarsia to the base. Let
it cure overnight.
9) Polish the entire intarsia as if it was a cabochon. Having stones with
similar hardness makes it easier to polish the intarsia.
The intarsia process can be difficult, tedious, and time-consuming. Some special pieces of equipment make the work easier. Specifically, a lap with a fence to help ensure edges are flat speeds up the process.
Flat Lap Machine with DIY Fence
You can buy a commercial intarsia machine with built-in fences from Highland Park (https://hplapidary.com/collections/intarsia-machines), or you can make a fence for an existing flat lap machine as shown in the photo above. There are many other options for making your own fence as discussed here: