Zircon |
| ZrSiO4 |
| Tetragonal |
Forms
c(001), a(100), m(110), p(111), u(331), x(311), y(411),
z(511)
| Forms | Illustrations | |
| 1 | m, p | |
| 2 | m, p, u | Figure 138 |
| 3 | c, u, m, p, u, x, y, z | Figure 139 |
Occurrence
Zircon is found sparingly in the pegmatite of the Trotter mine at Franklin in dark-brown
crystals of ordinary form and habit (figure 138).
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Figure 138 Crystal of zircon showing the forms m(110), p(111), and u(331). Balls Hill, Franklin. |
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It is not known as a constituent of the zinc-ore deposit, nor has it been reported from Sterling Hill.
A remarkable series of specimens of zircon preserved in the Canfield collection was found near the Hill iron mine on Balls Hill a little south of Franklin. The main group consists of 16 crystals implanted on rough pyroxene and dark-brown garnet. The largest zircon is 2 inches long and half an inch square. The crystals are black and of splendent luster and show only the forms (110), (111), and (331). Other specimens from the same cavity, the only one found, show doubly terminated crystals of greater complexity, as shown in figure 139.
| Figure 139 Crystal of zircon showing the forms c(001), a(100), m(110), p(111), u(331), x(311), y(411), and z(511). Balls Hill, Franklin. |
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In grouping, brilliance, complexity, and large average size of crystals these specimens of zircon are unique, and they are among the most striking features of the Franklin series of minerals. Plate 16, A, shows the best group of them in the Canfield collection.
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Website
© by Herb Yeates 1997-2006.
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page created: August 12, 2006 7:23 PM
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