Pow! You're now in possession of an assortment of lumps of crystal, some clear, some cloudy, some opaque. They could be geological samples, or uncut gems, or semi-precious rocks useful as little more than paperweights. All you know is that they're not yours and they're in sachets marked "Made In India".
How do you go about turning them into money?
I'll play! (note, I actually agree with MarkB, but the mental exercise to figure out how to unload the loot is fun)
Let's assume that I've already deduced that my sudden posession of the pile of rocks might be considered illegal to some people. At least they may think I committed a crime. That's actually the first challenge, is not making a mistake during the initial happy dance phase.
So we enter the Discrete Investigation phase.
I need to know what these are. I might do a bit of googling, and sort the rocks by apparent type (assuming a mix, rather than all diamonds in various forms). Next, I will identify rock/rock experts and discretely take SMALL samples to each. I will not flood any single expert. The rock(s) I take to an expert will have a simple story such as I inherited them from a rock collecting uncle. This way I avoid risking saying the wrong place like finding diamonds in an old mine in Arkansas when diamonds have never been found there (how would I know, I'm not the expert as I don't even know what kind of rocks these are).
Once I learn what kind of rocks most of the examples in my inventory is, I can identify the rest. I expect to be LEARNING some rock stuff from the expert, so I can validate the rest that I thought were the same myself. I'll also learn WHERE these kind of rocks can be found, as I'll need that to build a better story for the selling stage.
Next is the Learn the Market and Provenance phase.
I need to know the best way to sell these (E-Bay, gem shows, etc) and if there's any expectation of documentation (like these are blood diamonds from Africa). If I had a gem cutting friend and a jewelry making friend (I have the latter), I'd turn all this into jewelry and sell that, as there's little red-tape on that (barring expensive jewelry that you buy insurance for).
Otherwise, assuming I am trying to just unload these will be tricky. A place that does gem cutting to make jewelry probably works with their sources. Cutting into that would look suspicious (psst! Wanna buy some rough rubies?). One might be able to sell them one at a time on E-Bay, but that's a lot of sales, which if there was a question, would stand out pretty bad. If there was no question, it'd be a piece a cake to do, but pretty slow.
I'm thinking that the way to unload them enmasse is to befriend a jeweler. Learn where their supplies come from. Then befriend that guy. Learn where he buys from, and befriend that guy. Work your way down the chain until you find a "safe" spot to show up with some rocks to sell. Of course, the farther down the chain you are, the less money you'll get, but you need to be selling at the rough stones end of things anyway. A guy who uses fine gems in his jewelry isn't interested in ugly rocks that have diamonds in them.
It's definitely a lot of research to do this. Possibly some travel. I'm not sure, without the right connections, if the cost to get hooked in from scratch is worth the pay off because as rough stones, these things sell for lower prices anyway.
