A lithium-rich granite pegmatite most famous for its manganese phosphates (Brush and Dana (1878, 1879, 1890)) and alteration of spodumene (Brush and Dana (1880)), which occurs in scattered crystals in a matrix of cleavelandite. About 40 percent of the spodumene is unaltered; the remainder is altered in various degrees - by very fine-grained, parallel fibers of albite and eucryptite or by further alteration to “cymatolite” - fine-grained, parallel fibers of albite and muscovite. Extreme alteration resulted in replacement by yellow, fine-granular microcline or greasy, greenish "killinite" or "pinite". Individual crystals may show in cross-section a continuum of these states of alterations.

The manganese phosphates, of which lithiophilite is the most common, occur in rare, scattered concentrations within the cleavelandite-spodumene unit. There are two kinds of concentrations: (1) those in which lithiophilite and manganapatite are the sole manganese phosphates and (2) those in which three or more phosphate minerals are present. Yellowish-brown lithiophilite occurs in isolated ellipsoidal nodules ranging from ¼ inch to more than 1 foot in length. The nodules are invariably coated with bluish-black manganese oxide.

The discoverer of the new minerals is controversial, but research by Januzzi (1997) indicates that the original quarrier Abijah Fillow set some of the unusual minerals aside in 1876–77. In the late summer of 1877, James D. Dana took some of them back to Yale. The following year George J. Brush announced the discovery of a new mineral that the Reverend (and mineralogist) John Dickinson had found at the quarry in 1877. Following this, Brush and Edward S. Dana worked the quarry with Fillow for specimens of new minerals, and Dickinson donated additional specimens from his first visits in 1877. Clearly, both Dickinson and Fillow deserve credit and were given so with new mineral names.

According to Cameron et al. (1954):



Januzzi (1997) reports that when the Union Porcelain Works operated the quarry in 1880-90, it was known as the Smith Mine. During that time three to four thousand tons of feldspar and four thousand tons of quartz were shipped.

Elwell (1937) reported that in 1934:



The quarry and underground workings have been inactive since 1944, and most of it is flooded.

Cameron et al. (1954) state the following:



Another detailed description of the pegmatite's structure is given by Shainin (1946).

In the late 1970s, an attempt was made to open the site to educational mineral collecting (as opposed to a mine or quarry). The town government decided such an operation should be regulated like a school, placing so many obstacles on what should have been a very simple program that the attempt was abandoned.

Note that the quarry is located in the Town of Redding, but that the village of Branchville, situated immediately southwest of the quarry, is actually in the neighboring Town of Ridgefield. Because of the long history of the use of "Branchville" as a place name for this locality, it is included in the hierarchy.

Other Regions, Features and Areas containing this locality

References