Hi Caitlin,
I would not recommend buying a table-mounted circular saw for the purpose, but some jewelers and most plumbers or hardware stores will know somebody with one or have one themselves and do it for you. You can always mount the halves in round cabochon settings for earrings. That's what I do with my testing specimen. It is also a good way to find out whether the color is natural or not (diffusion leaves a rageddy color fade inwards from the surface and the drill hole, irradiation and heat treatment only from the surface inwards) or if the pearl was probably reinserted (chonchiolin intermediate layers, abrupt color changes, although that sometimes also happens in natural pearls, e.g. in environmental changes like salinity shifts, food scarcity, abundance, diseases etc..).
If you do it yourself, watch out for your fingers. Use the little plungers to remove hard contact lenses to hold the pearl. If they shake loose (that will inevitably happen at most inopportune moments) DO NOT!! follow your knee jerk reaction and reach for the pearl. Turn off the saw, get the plunger back on and start anew. If you want to be safe, put some Elmer's School Glue on the plungers first and let them bond thoroughly with the pearl. Elmer's comes off easily afterwards the way Vigor does not.
Zeide