Composition
As shown by the analyses, manganese is found only in traces, a remarkable fact in view of the immediate association of hematite with franklinite.

Occurrence
The most characteristic form of hematite from Franklin consists of coarse granular masses showing exceptionally perfect rhombohedral parting. Some single parting surfaces have an area of several square inches, and large pseudocubic parting blocks of great brilliance, singularly resembling galena in color and structure, are often obtained. Such a mass is illustrated in plate 4, A.

One specimen of such material consists wholly of a uniform mixture of hematite with black franklinite that has an equally well developed octahedral parting, the whole having a most unusual mottled appearance. Commonly the hematite contains scattered grains of willemite, garnet, and calcite or it forms a crust surrounding crystals of franklinite. This granular hematite, which is not rare in the northern part of the mine, was found at times in masses weighing several hundred pounds. Moses (190) states that it has the rhombohedral angle of hematite) which as measured between the parting planes is 94° 13' and as computed for hematite is 94°. One crystal an inch across, flattened parallel to the base and showing strong parting, was wholly embedded in limestone.

Minute brilliant crystals of hematite were seen in a specimen of porous dolomite from the Buckwheat mine. They bore the forms of combination no. 8, being of tabular habit. Other specimens of the same dolomite showed hematite in minute globules of kidney-ore type, their surface coated with needles of goethite.

There is in the Fiss collection a specimen from the Trotter mine showing minute crystals of hematite of rhombohedral form with prism truncations, the dominant form probably being u (1014). These tiny crystals, in part individuals of perfect form, in part groups aggregated to form spheroids, were embedded in calcite.

The most complex hematite crystals yet found at Franklin were discovered in 1926 and described by Palache and Berman (251). They were found coating the surface of ore in an open vein, associated with calcite and colorless sphalerite in flattened twin crystals. They are small, not exceeding a quarter of an inch in length, and brilliantly metallic, with an iridescent luster, although some were lightly coated with a film of red iron oxide. The dominant form is the unit rhombohedron r(1011), which gives them a cuboid habit, as shown in figure 31.

Figure 31 Pseudocubic crystal of hematite showing the rhombohedron r(1011) slightly modified by c(0001) and z(2241). Franklin.

The enlarged detail of one coign of a similar crystal is shown in figure 33.

Figure 33 One coign of a rhombohedral crystal of hematite like that of figure 31 but showing the forms r(1011), e(0112), n(2243), z(2241), and the rare scalenohedrons c(1232), y(1235), and P(2467). Franklin.

The forms c(1232), y(1235), and P(2467) are negative scalenohedrons constituting a radial zone. Forms of that type are always rare on hematite. Although exceedingly minute, these faces are clean-cut and brilliant, giving excellent readings on the goniometer.

Several of the crystals are twins, the twinning being ion the common law for hematite—twinned on the base with a face of the first-order prism as the composition plane. Figure 32 shows a twin crystal with forms the same as those found on the simple crystals, but symmetrical distortion parallel to the composition plane gives an oblong or in some crystals a hexagonal habit to the twin groups.

Figure 32 Plan of a twin crystal of hematite showing the forms c(0001), r(1011), e(0112), n(2243), and z(2241). The twin plane is (0001), and the composition plane is (1010). Franklin.

Crystals of hematite associated with friedelite in an open seam in ore show the variable habits of figures 34, 35, and 36. Although rather rough, the crystals were sufficiently brilliant to give measurements establishing the forms shown.

Figure 34 Hexagonal tabular crystal of hematite showing the forms m(0115) and z(2241). Franklin.
	Figure 35 Prismatic crystal of hematite showing the forms a(1120), z(2241), r(1011), and m(0115). Franklin. The steep pyramid z is uncommon on hematite.
Figure 36 One end of a barrel-shaped crystal of hematite showing the forms c(0001), r(1011), n(2243), z(2241), and c(1232). Franklin.

Brilliant crystals of specular hematite are associated with the abundant specimens of sphalerite that were found in the northern part of the mine on the 300-foot level. The tiny plates stand free in cavities with sphalerite crystals. The base is brilliant, and the paper-thin plates show more or less complex modification. Combination no. 7 is an example of this type.

It may be noted that none of the figured crystals from Franklin have a habit common to crystals of hematite from any other locality.

As the coloring matter of jasper and other siliceous rocks and as an alteration product of franklinite, hematite is of widespread occurrence at both Franklin and Sterling Hill but is not a conspicuous mineral at either locality.