By far the cheapest route will be to educate yourself to learn the
differences between the real thing and the impostor, in this case I
would recommend either taking a colored stone course from GIA, or
spending some time with a knowledgeable expert and let them show you
the differences. Your not asking to get a certification, you just
want to know if they are the real thing, correct? I don’t know anyone
that is serious about this business, that doesn’t have a good handle
on properly identifying stones that come into their possession. If
you want to elevate your understanding and position past the point of
being a hobbyist, then you should get to know gemstones inside and
out. Sometimes your local Jewelers or Gemological association will
haveshort courses to participate in that will help, some GG’s offer
tutoring as a sideline. You will be far better off if you learn the
skills you need yourself, then to spend the 30-150 dollars per stone
- shipping every time you have a question. Education is never wasted.
Hope this helps.