Figure F3. CL spectrum showing Mn-activated luminescence. The emission of Mn²⁺ in dolomite depends on the substitution site and is characterized by a main emission band between 590 and 620 nm and a strong secondary band between 640 and 680 nm (Machel et al., 1991). The first band is the result of Mn²⁺ substituting for Ca²⁺, and the second records Mn²⁺ substituting for Mg²⁺.