Cyclosilicates iolite, emerald and tourmaline
The ring silicates (cyclosilicates) iolite, beryl and tourmaline have crystal structures that contain channels large enough to house individual impurity molecules which can exhibit spectral properties similar to their normal vapour forms. These three minerals typically contain molecules of water that show infrared absorptions that are both narrower and at a shorter wavelength than liquid water (shown as the broad blue band in the plot here). The trapped molecules in these channels can remain 'bottled up' for periods as long as the age of the Earth and can sometimes be sampled to reveal magma histories from very early in the history of our planet.
The images of rough crystals above are, from the left, iolite, emerald and pink tourmaline. The strong water absorption bands can be seen around 1400 and 1900nm.
Cyclosilicates iolite, emerald and tourmaline
The ring silicates (cyclosilicates) iolite, beryl and tourmaline have crystal structures that contain channels large enough to house individual impurity molecules which can exhibit spectral properties similar to their normal vapour forms. These three minerals typically contain molecules of water that show infrared absorptions that are both narrower and at a shorter wavelength than liquid water (shown as the broad blue band in the plot here). The trapped molecules in these channels can remain 'bottled up' for periods as long as the age of the Earth and can sometimes be sampled to reveal magma histories from very early in the history of our planet.
The images of rough crystals above are, from the left, iolite, emerald and pink tourmaline. The strong water absorption bands can be seen around 1400 and 1900nm.