of' Several Minerals. G9 



Mohs ; such species as are not yet enumerated in that sys- 

 tem I have mentioned in those orders where they are likely 

 to be included in future, and marked with an asterisk ; such 

 as could not be included even in this manner, are reserved 

 for an appendix. 



Order I. Haloide. 



1. Gypsum, a perfectly white transparent crystal, from Oxford, 2.310 



2. Anhydrite, a rectangular four-sided prism, obtained by cleav- 

 age, grey, semitransparent, from Hall, Tyrol, 2.899 



3. Alumstone, the crystallised variety on the surface exposed in 



the drusy cavities, from Tolfa, 2.694 



4. The compact part of the same specimens, 2.671 



5. Kryolite, the white cleavable variety, 2.963 



6. Apatite, massive, asparagus-green, transparent, from Salzburg, 3.180 



7. Apatite, asparagus-green crystals, from Cabo de Gata, 3.22.5 



8. Fluor, combinations of the hexahedron and octahedron, dark 

 violet-blue, from St. Gallen, Stiria, 3.140 



9. Fluor, an octahedron obtained by cleavage, of a greenish- 

 blue colour, from the Hartz, 3.163 



10. Fluor, twin-crystals, pale violet-blue by reflected Ught, yel- 

 lowish white by transmitted light, Alston, 3.177 



11. Fluor, an octahedron obtained by cleavage, pale violet- 

 blue, Alston, 3.178 



12. Arragonite, yellowish-white, perfectly transparent crystals, 

 from Bohemia, 2.931 



13. Calcareous spar, a brown cleavable variety, 2.715 



14. Calcareous spar, another brown cleavable variety, but pre- 

 senting curved faces of cleavage, 2.721 



15. Calcareous spar, crystallised in the form (P+l)3.R+ao, 

 white, semi-transparent, from Alston, Cumberland, 2.721 



16. Calcareous spar, yellowish grey, small individuals, aggre- 

 gated in a granular composition, 2,727 



17- Calcareous spar, individuals of a columnar composition, 

 honey-yellow, semi-transparent, 2.731 



18. Calcareous spar, in large cleavable individuals, of a reddish- 

 brown colour, owing to the admixture of oxide of iron. This 

 variety was sent from Paris to the collection at Gratz, as Chaux 

 carbonatee ferrijere, 2.778 



19- Calcareous spar, white translucent cleavable masses, en- 

 gaged in the hydrate of magnesia from Unst, (see Order V. 20.) 2.647 



20. Calcareous spar, crystals of the form of the fundamental 

 rhombohedron, associated with small crystals of adularia, epidote, 

 and chlorite, from Dauphine. 2.508 



This is a remarkable variety. I could not find a difference 

 in its angles or in its hardness from Iceland spar, and yet 

 the substance seemed perfectly homogeneous. 



