Demantoid Garnet Engagement Ring 20

 Demantoid Garnet Ring.
By Aamir Mannan.                  DEMANTOID GARNET
The most valuable and most attractive of the garnets, the green garnet demantoid, is the variety of the  calcium-iron garnet andradite. Here again we have an iron spectrum(iron) with enough chromium to enrich the colour and show chromium lines in the red. The iron band is an strongly intense one, centered at 4430 A. This is far enough into the blue-violet to be difficult to see as anything more than a sharp cut-off to the
end of the spectrum, specially where chromium is present and causing general absorption of the violet. In paler stones and with good lightning conditions, the band can be seen complete though very strong it is not very wide. The chromium lines are easily seen in the specimens the doublet is very deep in the red, and there are weaker and rather diffuse lines at 6400 and 62I0 A.