How do you cut ethiopian opal slices

I was wondering how to cut slices of ethiopian opals. What I am trying to accomplish is cutting a slice and inlaying that slice in to another medium.

Perhaps someone can make a suggestion on what to inlay it in.. I attached some pictures of a pendent my friend has, and were trying to make a simalar ones... I also need to know what equipment I need to do this project... Thanks

There are many books out there in the libraries or through inter library loan, or in rock shops and book stores on Intarsia and inlay work. The late
Dr. John Sinkankas, wrote of it in many of his books on lapidary work, so there is a plethora of information on the techniques of inlay and inlay materials, Ryan. The nature of Ethiopian opal, may require it to be inlaid in a resin medium to preserve and protect it from the air. You can cast it into resins of contrasting colour with a clear resin over the top surface.
I say this because I believe that most of the ethiopian opal that I have seen is inherently unstable and tends to crack.So job one, is to find, a stable piece of rough that has good colour and has been out of the ground and not in water for at least a year. This instability problem plagued Mexican and some Brazilian opals for years, and now, dealers and miners test rough first, by leaving it out to dry for at least 6 months, and I haven't heard of this being done much , so far, with the Ethiopian material, despite it's relatively high pricing structure.
So good luck Ryan,and I hope that your piece of rough is both beautifully blessed with both stability and many internal flashes of colour, which would lend itself to being inset into almost any material.

Sorry, Ryan , I ran off on a tangent and missed part of what you were inquiring about. Since most of the Ethiopian material I have seen seems to be in nodules and tubelike formations, and it is relatively soft, it can be cut in cross section to best expose whatever play of colour it may have within the rough. To accomplish this you would need access to a thin bladed diamond trim saw. One can often access one of these, if you don't want to lay out cash for one, via a local gem club who often have cutting workshop space available for members,and these usually have more than one size of diamond saws. Opal is soft enough that you can then hand "lap" the flat cut surface by rubbing in under water on a very fine wet or dry silicon carbide or diamond sandpaper. These can usually be purchased in a rock shop and even in a good hardware store. I recommend finishing be started [with patience] with a 1200 or finer grit, and finalized on a felt wheel with a slurry of tin oxide polishing compound or a really really fine diamond polishing suspension medium. Remember that any grooves or scratches that you miss in the early coarser grits will come back to haunt you and be pretty well impossible to remove in the super fine finishing grit papers. So take your time at the beginning and look the surface over carefully with a loupe or a magifocus to assure yourself that you have removed all marks and grooves from the sawing and subsequent shaping processes, before moving on to grinding away the surface with the next finest grit level papers.You should move along in a progression of continually finer and finer grits until you get a glossy and very smooth surface, and at that point you move to the polishing stage.
Hope that this is of some help to you Ryan.
Ray