Cocaine a cola....

[ProfessorGAC]

11. The Stuff Going To Pharma...

...is 99.4% minimum. That's the lower specification!
The test is done 2 ways.
One is the melt point you described, except it's an automated test now. A laser shoots at the capillary and when it melts (and highly pure materials tend to all melt at once instead of what's called Krafting). When it goes liquid, the laser shines through it and hits the detector.
Measures melt point to 0.01 degrees C.
The other method is spectrochemical.
The average of these shipments was a little over 99.8% pure.