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 | |
| | | | | |
Iron | 6 |5.0|Burns and yields | |Brass |Cubical.
pyrites |to 7 | |a black globule, | | |
| | |decrepitates | | |
| | | | | |
Copper | 3 |4.2| do. do. | | do. |Tetrahedronal.
pyrites |to 4 | | | | |
| | | | | |
Stilbite | 4 |2.2|Intumesces and |Difficult; jelly |White |Like Fig. 8.
| | |fuses readily |on long boiling | |
| | | |with nitric acid.| |
| | | | | |
Laumonite | 4 |2.3|Intumesces and |Readily | do. |Generally
|to 0 | |fuses to frothy |gelatinizes | |chalky.
| | |mass | | |
| | | | | |
Heulandite| 4 |2.2|Intumesces and |Soluble, no | do. |In right
| | |readily fuses |jelly | |rhomboidal
| | | | | |prisms.
| | | | | |
-------------------------------------------------------------------------------
To Distinguish the Minerals together the one from the other.--Calcite by effervescing on placing a drop of acid upon it. Natrolite resembles stilbite, but may be distinguished by gelatinizing readily with hydrochloric acid and by not intumescing when heated before the blowpipe; from the other minerals by the form of the crystals and their setting, also the locality in the tunnel in which it was found.
Pectolite sometimes resembles some of the others, but may be readily distinguished by its tough long fibers, not brittle like natrolite. Datholite may generally be distinguished by the form of its crystals and their glassy appearance, with great hardness, and by tingeing the flame from the blowpipe of a true green color. Apopholite is distinguished from calcite, as noticed under that species, and from the others by its form, difficult fusibility, and part solubility.
Phrenite is characterized by its hardness, greenish color, occurrence, and action of acid. Iron pyrites is always known by its brassy metallic aspect and great hardness. Copper pyrites, by its aspect from the other minerals, and from iron pyrites by its inferior hardness and less gravity.
Stilbite is characterized by its form, difficult gelatinizing, and intumescence before the blowpipe; from natrolite as mentioned under that species.
Laumonite is known by its generally chalky appearance and a probable failure in finding it.
Heulandite is distinguished from stilbite by its crystals and perfect solubility; from apopholite by form of crystals.
In the next part of this paper I will commence with Staten Island.