_Chrysorolla_.--This mineral, very abundant in this locality, resembles malachite, but has a much bluer, lighter color, without the fibrous structure so often present in malachite, and seldom in masses, it only occurring as light druses and incrustations, some of which are very beautiful, and make very fine cabinet specimens. Its hardness is less than that of the other species, being under 3, and a specific gravity of only 2, but as it frequently occurs mixed with them, is difficult to distinguish. It does not dissolve in nitric acid, although that takes the characteristic green color of a solution of nitrate of copper, as from malachite or red oxide. This species is found all over this locality, and a fine drused mass of it will form an excellent memento of the trip. _Copper Glance_.--This mineral is quite abundant in places here, but fine crystals, even small, as it all is, are rare. That which I have seen has been embedded in the loose rock above the mine, about a quarter inch in diameter, and more or less disguised by a green coating of chrysocolla. The color of the mineral itself is a glistening grayish lead color, resembling chromite somewhat in appearance, but the crystals of an entirely different shape, being highly modified or indistinct rhombic prisms. The specific gravity is over 5, and the hardness 4. Before the blowpipe on a piece of wood charcoal it gives off fumes of sulphur, fuses, boils, and finally leaves a globule of copper. In nitric acid it dissolves, but the sulphur in combination with it separates as a white powder. A steel knife blade placed in this solution receives a coating of copper known by its red color. _Erubescite_--This mineral occurs massive in the rock here with the other copper minerals, and is of a yellowish red color, more or less tarnished to a light brown on its surface, Before the blowpipe on charcoal it fuses, burns, and affords a globule of copper and iron, which is attracted by the magnet. Its specific gravity is 5, hardness 3. It resembles somewhat the red oxide, but the low gravity, inferior hardness, lighter color, and blowpipe reaction distinguish it. These are the only copper minerals likely to be found at this mine, and the following table and note will show their characteristics: Name. Speci- Hardness Action of Action of Color. Form. fic Blowpipe Heat. Hot Nitric Gravity. Acid. Mala- From 4 From 3 Decrepitates, Dissolves Pure Oil Fibrous, chite to 4.5 to 4 but fuses with with Green. massive, borax to a effer- or in- green bead. vescence crusting.