Extended Data Fig. 2: FTIR spectra of the 1.5 ct diamond.
From: Hydrous peridotitic fragments of Earth’s mantle 660 km discontinuity sampled by a diamond
The spectrum was baselined in GRAMS software and normalized by two-phonon diamond lattice bands at 2460 cm−163, showing that it is a pure type IaB diamond with only B center nitrogen. Inset figure (a) shows hydrogen related peaks at 3107 and 3085 cm−1, which are typical in milky type IaB diamonds64,65 and consistent with the milky feature observed around inclusion 3. Inset figure (b) shows B center nitrogen at 1172 cm−1 with no detectable A center nitrogen and very weak residual IR absorption at 1367 cm−1 caused by hydrogen related defects incorporated into platelets that quench the platelet IR absorption66.
