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Calamine, Zinc Carbonate, occurs in the same way in relation 

 to Blende, or Zinc Sulphide, as Cerussite does to Galena; and, 

 like it, also originates from the decomposition of the sulphide. 

 Calamine, however, is not of very common occurrence, even where 

 Blende is found in abundance. This may be due to the fact that 

 the decomposition of Blende gives rise to the Sulphate, whose 

 instability favours its removal in solution almost as fast as it is 

 formed, while the conditions for the formation of the Carbonate 

 are not usually quite as favourable. Calamine usually occurs in 

 connection with the rider, or fault-breccia, of mineral veins, generally 

 in such parts of the vein as are within the influence of carbonated 

 waters percolating downwards from the surface. 



The principal localities in the two counties are in the neighbour- 

 hood of Alston, especially at Farnberry Mine. Other localities are 

 the mines situated on the steep south-western edge of the same great 

 upland tract, more especially at Dufton ; and the mines in and around 

 what are known as the Caldbeck Fells. The Alston specimens 

 occur chiefly in the form of encrusting groups of spheroids, with a 

 concentric banding resulting from deposition in successive layers, 

 and with a radiate structure due to the presence of the separate 

 prisms. Considerable variety in both external form and colour 

 may be observed, some appearing hke dull, chalky-looking encrust- 

 ations, investing portions of fault-breccia, while others assume the 

 character of groups of a more-evidently crystalline character. The 

 prevailing colour is a peculiar dull greenish-yellow, something 

 between gamboge and a pale tint of olive; and the same specimen 

 not unfrequently exhibits a variety of tints in different layers, 

 which, when the mineral is cut and polished for inlaying or other 

 ornamental purposes, give rise to a very pleasing effect. Similar 

 fibrous radiating groups of the same general tint occur at Dufton, 

 and the mines in the districts adjoining. 



The Caldbeck Fell specimens mostly come from Rowtin Gill, 

 and occur there also as dull chalky-looking encrustations on the 

 materials composing the fault-breccia. In tint these vary from 

 smoke grey, or dull lead-colour, through sapphire-blue, or lavender, 

 to nearly a cobalt-blue. It is remarkable that, though Blende is 



