This is for informational purpose as this test is destructive.
If you want to check if a turquoise stone in your possession is natural or a resin, you will have to burn it with a blowpipe.
This test can be made if you have a rough stone or several stones from the same lot.
Step 1: Burn Them
Set the stones you want to test in a crucible.
Burn them with a blow pipe during 2 minutes.
Step 2: Analyze
Check the result of what you have obtained.
If you have ashes then you had a resin type of stones.
If you still have stones that turned white, then you have tested natural turquoise stone.