_Heulandite_.--This rare mineral has been found under the same conditions as laumonite in Shaft No. 2, but it is seldom to be met with, and then in small crystals. It is of a pure white color, sometimes transparent. It intumesces and readily fuses before the blowpipe, and dissolves in acid without gelatinizing. Hardness 4, specific gravity 2.2. The few other minerals occurring in the tunnel are so extremly rare as not to be met with by any other than an expert, and it is impossible to detail the localities, as they generally occur as minute druses or incrustations upon other minerals with which they may be confounded, and have been removed as soon as discovered. The minerals referred to are analcime, chabazite, Thompsonite, and finally, the mineral which I first found in this formation, Hayesine, which is extremely rare, and of which I only obtained sufficient to cover a square inch. The particulars in regard to its locality, etc., maybe found in the _American Journal of Sciences_ for June, page 458. I will now sum up the characteristics of these several minerals of this locality in the table: ------------------------------------------------------------------------------- | | | | | | Name. | H. |Sp.|Action of |Action of |Color.|Appearance. | |Gr.|Blowpipe. |hot acid. | | ----------+-----+---+-----------------+-----------------+------+--------------- | | | | | | Calcite | 3 |2.6|Infusible, |Soluble with |White |Like Fig. | | |but glows |effervescence | |3 and 4. | | | | | | Natrolite | 5 |2.2|Readily fused |Forms a jelly | do. |Like Fig 5. | | |to clear globule | | | | | | | | | Pectolite | 4 |2.5| do. | do. do. | do. |Divergent | | | | | |fibers, Fig. 6. | | | | | | Datholite | 5 |3.0|Intumesces, fused|Forms a jelly |Color-|Small, nearly | | |to clear globule,| |less |spherical, etc. | | |gives green flame| |white | | | | | | | Apopholite| 5 |2.5|Difficult, fused |Partly soluble |Tinted|Like Fig. 7. | | |to opaque globule|in nitric acid | | | | | | | | Phrenite | 6 |2.9|Intomesces, fused|Partly soluble |Green-|In tables and |to 7 | |to clear globule |in nitric acid, |ish |incrustations. | | | |leaving flakes | | | | | | | |