Hidden — Mineral Research in Llano County, Texas. 427 



without heating it. Enormous crystals of orthoclase were 

 common, some over five feet in diameter. Quite frequently 

 small veins of very perfect red feldspar crystals (highly- 

 twinned), and upon which albite crystals were attached, were 

 found bordering the fluorite and penetrating it. In the feld- 

 spar, well crystallized menaccanite was sometimes observed, 

 and this mineral is new to the locality. Yellow rutile, of the 

 sagenitic variety, was observed in only one instance and then 

 upon smoky quartz crystals. Polycrase, or an allied species, 







^^*"^B 









f 









'"''* 







V A mm ■»*** 























,, 







_^=^. — ( 



18-Ib. mass of Yttrialite. 



was seen implanted upon the gadolinite, this is also new to the 

 region. A cavity into which a horse could have been put was 

 discovered on the river side of the mine, and from it a large 

 crystal of smoky quartz was taken that weighed over six hun- 

 dred pounds. It was forty-three inches high and twenty-eight 

 inches broad and fifteen inches thick. This is now in the 

 University of Texas collection at Austin, Texas. 



Very fair amethysts were found in the west end of the hill, 

 in cavities in the feldspar. Masses of biotite, four feet across, 



