A spline baseline adjustment is applied. The identification of this mineral has been confirmed by X-ray diffraction and chemical analysis. Unoriented sample. Instrument settings: Thermo Almega XR 532nm @ 100% of 150mW. Data as given by the link, used in the range from 2500 to 4000 cm -1 . A spline baseline adjustment is applied. By Wopenka and coworkers, we find stressed that the natrolite group members have water inside, "and the specific positions of the H2O molecules are controlled by the regular arrangement of the channels and cages that exist in a given crystal lattice". The peaks observed in the OH-stretching region "are among the most characteristic ones for a given natrolite group mineral and can be used for unambiguous identification. Natrolite, mesolite, and scolecite (all structural type 3) are characterized by several sharp peaks in this spectral region, and thomsonite and gonnardite (both structural type 2) have a broad unresolved double peak feature, whereas edingtonite (structural type 1) has a medium wide single peak. Among the six members of the group, mesolite has the weakest bands in the OH stretching region, followed by gonnardite. The other four natrolite group minerals are all characterized by strong bands in the OH spectral region. Scolecite, which has the most characteristic feature in the OH stretching region, is characterized by five narrow well-resolved peaks" .