Monday, December 23, 2013

Uncommon appearance of common minerals or I wish Mn would be more abundand element.

Mn-rich andalusite ("viridine"):
The black bar on the right equals 500um. Two pictures represent 90-degree-rotation of a microscope stage.
 Mn-rich epidote ("piemontite"):
These Mn-rich metamorphic rocks were found in Australia by Dr. Alfredo Camacho, who kindy let me take and post the pictures.
More pictures:

Tuesday, December 17, 2013

Raman spectroscopy

Today I had a chance to work on a Raman spectrometer. A hooked-up microscope allows to make measurements in situ. Surprisingly, thin sections with cover glass are also applicable!
So, let's take a suspicious zircon-looking grain. Its irregular shape and thus, unavailability to determine extinction cast doubts on the identification verdict. After ~50 seconds, the spectrometer gives a beautiful spectra. However, it is not enough to identify a mineral (in my case). The link provides us with 100% zircon and its Raman spectra which is almost identical. Ta-da.