Plain English
What it means
Gem identification uses multiple independent properties rather than appearance alone.
Why it matters
It is the practical context in which RI, specific gravity, microscopy, spectroscopy, and other observations become useful.
What it does not tell you
The tests required depend on the material, condition, mounting, and question asked.
Evidence
References
- 1Analysis of Gemstones at GIA Laboratories
Gemological Institute of America
Open source