Cathodoluminescence spectra of a suit of natural fluorites from several main fluorite deposits of China were measured.The main lines in the spectra of all samples studied

except Mo-25

are due to Dy

3+

and Sm

3+

ions substituting for Ca

2+

.A few lines arising from Er

3+

Pr

3+

and Tb

3+

are also observed.The relative intensities of spectral lines are closely related to the relative contents of individual rare earth ions in the sample.Group theory analysis shows that the local symmetry of Dy

3+

in fluorite is lower than cubic and/or there may exist more than one Dy

3+

environments.In the spectrum of Mo-25

only a broad band centered at 490 nm occurs in the visible region.This band is probably due to the

4

T

1g

S(G)-

6

A

1g

(G)transition of Mn

2+

ions.Because the crystal-field splitting parameter Dq of Mn

2+

in fluorite is anomalously low

grean emission is observed

which is unusual for eightfold-coordinated Mn

2+