Evaluation of portable Raman instruments with 532 and 785-nm excitation for identification of zeolites and beryllium containing silicates
Abstrakt
In this short paper we present Raman spectra of minerals of the group of zeolites and beryllium containing silicates (thomsonite, stilbite, natrolite, euclase, phenakite, bavenite, milarite and beryl) obtained indoors/outdoors on a collection of samples using a portable 532-nm/785-nm systems. This study complements a previous one in which one of the first handheld 785-nm excitation instruments was tested.
To our knowledge this is the first time that a handheld Raman spectrometer equipped with a 532-nm laser as well as a portable dual instrument with 532/785-nm excitation was used in mineralogy. For the major findings of the zeolites investigated, the most intense Raman bands are found at correct positions +/-2-4cm(-1).
Although acceptable results were obtained using the 532-nm excitations with both the instruments (the strongest bands are well developed and these bands permit the unambiguous identification), the use of the near-infrared excitation can especially be recommended (higher number of bands at correct positions, spectra with a S/N similar to laboratory spectrometers).