PETROGRAPHY OF TEE KEWEENAWAN 



653 



TABLE VI 

 Analyses of Laumontite and Related Products 



1. Light-pink laumontite, Pine City, Minn. F. F. Grout, analyst. 



2. Dark-red laumontite. Pine City, Minn. F. F. Grout, analyst. 



3. Dark-red laumontite. Kettle River, Minn. F. F. Grout, analyst. 



4. Lightest fraction of red pseudo-amygdaloid. Crooked Creek, Minn. This is 

 not a clean separation from feldspar, as shown by the next sample. F. F. Grout, 

 analyst. 



5. Next to the lightest fraction of the foregoing sample, No. 4. F. F. Grout, 

 analyst. 



6. Green pseudomorph after laumontite like sample No. 2. F. F. Grout, analyst. 



7. Appeared to be bleached and further altered from sample No. 6. F; F. Grout 

 analyst. 



8. Amygdules of similar appearance, Upper Tamarack Creek, Minn. F. F. 

 Grout, analyst. 



9. Pseudo-amygdules of similar appearance, associated with chlorite and hematite, 

 Upper Tamarack Creek, Minn. F. F. Grout, analyst. 



SiOz.. 

 AI2O3. 

 Fe^Oa. 

 FeO... 

 MgO.. 

 CaO.. 

 Na^O. 

 K2O.. 

 H2O- 



CO,... 

 TiO,.. 



Specific gravity 



51-34 

 22 .48 



0-S5 

 0.15 

 0.97 



10.68 

 1.23 

 0.40 

 1.66 



10.14 

 o.io 



49.66 



21.15 

 1.32 



0.21 



1.44 



9.16 



1.49 



1.38 



2 .90 

 10.80 



49-44 

 20.62 

 2.86 

 trace 

 1 .29 

 9.46 

 0.60 

 1.66 

 2 .40 

 11.97 



0.18 



48.85 



25.01 



2.19 



trace 



1-73 

 6.84 

 2.36 

 2 .21 

 2 .00 

 9-34 



0.10 



53-58 

 26.16 



1 .67 

 5-56 

 3-90 

 3.16 



53-02 



20.55 

 1.94 

 1 .36 



7-31 

 0.08 

 0.72 

 6.20 

 1.82 

 5-36 



trace 



62.78 



15-52 



2 .06 



0.20 



3-19 

 none 

 none 

 5-82 

 6.23 

 4-50 



0.06 



48.80 

 19.63 



I 8.87 



7-50 

 trace 

 0.30 

 5-98 

 1-74 

 6.30 



0.77 



99-70 



99-63 



100.48 



100.63 



Incom- 

 plete 



99. 



98.36* 



100.36 



99-89 



2-353 



2-315 



2.381 



less 

 than 

 2.580 



2-581 



2.750 



2.677 



2.581 



* Two sets of duplicate analyses yielded consistently low summation. The alkali determination 

 showed the poorest agreement; and the figure reported is that from the two highest results which were 

 in closeagreement. Sulphur, and carbonic acid are not present in amounts sufficient to change the total 

 much. 



yields no jelly as laumontite does. By thorough treatment with this 

 acid and alkali, only 25 per cent is extracted and the extract resembles 

 the original except in having more iron and none of the sodium and 

 potassium. However, the addition of sulphuric acid, in the above 

 treatment, makes decomposition complete. As the orthoclase of this 

 same district gives only 3 per cent to this treatment, it seems certain 



