Sterrett — Tourmaline from /San Diego County, Cal. 465 



DESCRIPTION OF PLATE XXIV.* 



1. Olive-green crystal of the sixth type. 



2. Transparent, sea-green, with clear pink cap ; first type. 



3. Crystal with colorless middle part and pale pink ends ; first type. 



4. Transparent throughout ; lower half pale green, upper half pink ; 

 second type. 



5. 'Pink with cap of exquisite rose color ; second type, same as figure 4. 



6. Small pink prism penetrating the end of a quartz crystal. 



7. Rough sea-green crystal passing abruptly into a pink cap at the upper end. 



8. Distorted and flattened crystal of green color fading into pale pink at 

 the upper end. 



9. Distorted crystal shown in basal projection in figure 10 ; sea-green color 

 with an almost colorless cap slightly tinted with pink. 



10. Cat's-eye cut from a crystal with internal striations, which can be 

 seen running horizontally through the stone. 



11. Section cut from a crystal with a smoky brown core surrounded by a 

 light greenish brown layer and pink shell. . 



12. Rounded bunch of lepidolite mica with albite adhering to the lower part. 



13. Pink crystals coated with a crystalline incrustation of cookeite enclos- 

 ing quartz and lepidolite. 



14. Section broken across a crystal with a dark brown core and lighter 

 colored shell. 



15. Bent crystal ; the lower half is light pink passing into a pale green 

 middle and back to pink at the upper end. Where the crystal had evidently 

 been fractured by the bending, it has been healed by bands of fibrous tourma- 

 line with silky luster. 



16. A crystal of the fourth type. Grass-green cap at the upper end (analo- 

 gous pole in this case), with white middle and corroded dirty green cap at 

 the lower end. 



17. Group of transparent pale pink crystals; analogous ends free and 

 terminated by c and subordinate r'. 



' * Nine-tenths natural size. 



