Timms Hill (Tim's Hill), Haddam, Middlesex Co., Connecticut, USA

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A vein of oligoclase and smoky quartz similar to the Haddam chrysoberyl locality was uncovered at the top of the east-facing slope on Tim’s Hill in the early 19th century. It hosts cordierite (iolite) and was referred to in some old literature as “Iolite Hill”. Shepard (1837) stated that the cordierite “occurs in large massive individuals, having one very eminent cleavage. Its colors are various shades of blue and green, the former predominating...it is transparent in spots, and possessed of dichroism.” Several writers noted the alteration of cordierite to “fahlunite” and bright green “chlorophyllite”. Schorl crystals are also present as “short, doubly terminated black tourmalines (5 to 10 mm. in length).” (Foye (1922)). Williams (circa 1945) states that the “Oligoclase can be had in transparent clear masses.”

The lat. and long. of the primary cordierite locality on Tim's Hill is given below, but other smaller outcrops occur at the top of the slope for 250 meters of more along strike to the north and south. Much gedrite can be seen in these outcrops as well.

Regarding bismuthinite, Shepard (1870) reported, "large crystalline masses of bismuthine, more or less coated by bismutite, from a quarryman who had discovered them on the iolite hill...One of the specimens weighs about half a pound; and constitutes a deeply striated or channeled crystal." However, given the lack of further finds, Williams (circa 1945) suggests that the source was really the chrysoberyl locality, where it is well known, and that “the quarryman no doubt did not want to give the right locality.”

References

- Foye, Wilbur G. (1922): Mineral localities in the vicinity of Middletown. American Mineralogist v. 7, p. 4-12.
- Weber, Marcelle H. and Earle C. Sullivan. (November/December 1995): CONNECTICUT MINERAL LOCALITY INDEX. Rocks & Minerals (Connecticut Issue), Volume 70, No. 6, p. 403.
- Shepard, Charles U. (1837): REPORT ON THE GEOLOGICAL SURVEY OF CONNECTICUT.
- Shepard, Charles Upham, Sr. (1870): ART. XII. - Mineralogical Contributions, A new variety (species?) of Columbite. The American Journal of Science - Second Series, Volume L, 1870. p. 90.
- Schairer, John F. (1931): MINERALS OF CONNECTICUT. Connecticut Geological and Natural History Survey, Bulletin 51.
- Schooner, Richard (1958): THE MINERALOGY OF THE PORTLAND-EAST HAMPTON-MIDDLETOWN-HADDAM AREA IN CONNECTICUT (With a few notes on Glastonbury and Marlborough).
- Schooner, Richard (1961): THE MINERALOGY OF CONNECTICUT.
- Williams, Horace S. (circa 1945): ARTICLE FOR NEW YORK SOCIETY OF MINERALOGISTS. Brainerd Public Library, Haddam, Connecticut.
- Lundgren, Lawrence, Jr. (1979): THE BEDROCK GEOLOGY OF THE HADDAM QUADRANGLE. State Geological and Natural History Survey of Connecticut. Quadrangle Report No. 37
- Heinrich, E. Wm. (1950): Cordierite in pegmatite near Micanite, Colorado. American Mineralogist, vol. 35, p. 173-184.

Mineral List

Albite var: Oligoclase 'Allanite' Biotite Bismuthinite

Chlorophyllite Cordierite 'Fahlunite' Gahnite

Gedrite Ilmenite Magnetite Quartz var: Smoky Quartz

Schorl

13 entries listed. 7 valid minerals.