Lopezite (synthetic) - Czech Republic

Still using the Science-Surplus spectrometer with the Labram microscope
because of difficulties with the Labram spectrograph. 

The spectrograph's grating turret uses a d.c. motor and four spring-loaded 
switches to determine the turret position. These switches ride up and down 
on ratcheting ramps and I used a backing-up motor motion to try and back the 
motor against the ratchet but this wasn't sufficient. The exact position 
was never consistent causing the wavelengths to shift back and forth considerably
while the whole turret was scanned (during the stitching of detector windows).
Temporarily I've put some painter's tape to fix the grating to 1800 and 
that solved the problem, but I'll need to figure out how to brake the 
motor against the ratchet. Because of this problem I'll probably have to 
go back and recalibrate everything.

[later, a "brake" check box was been added to the user interface that activates
 or releases grating turret braking. ]

Also still having trouble mating the output from the Raman filter to the 
slit entrance of the spectrograph...

[later, the laser diode inside the spectrograph was hooked up to allow
 reverse alignments]

Here's the second specimen we've measured (another easy one for 633nm recommended
by jm-derochette). Lopezite (potassiun dichromate, toxic, once used in older photography).





Background subtracted, cropped, and baseline corrected (black); matched to RRUFF database (blue) using CrystalSleuth:


background subtracted data (.csv)

RRUFF R070043 Lopezite