"chemical composition of gemstones"

[noncents]

Found this chart and thought it might be of interest

 

[silver]

Even the chart is pretty. It would be nice to have a chart like that that shows their light deflection angle in degrees as well, maybe organised from slightest to greatest !

 

[Westaus]

Looks good, is there a way to breakdown/test some gems to get chemical comp or is this just for the higher end labs and so on ?

Hardness I understand.