Roberts Mica prospect, Haddam, Middlesex County, Connecticut, USAi

Regional Level Types
Roberts Mica prospect	Prospect
Haddam	Town
Middlesex County	County
Connecticut	State
USA	Country

The prospect lies on rolling upland, about 3,000 feet south of this point along a poor woods road. The property is owned by Earl C. Roberts of Chauncey Road, Middletown. It was not under lease, and no exploration work had been done when it was examined by V. E. Shainin in March 1944.

The pegmatite lies in quartz-mica schist (Bolton schist) and appears to be a nearly vertical lens that strikes approximately N. 10° E. It seems to be 200 feet long and 100 feet thick. It has a poorly defined border zone and a core that encloses irregular pods and is cut by a fracture-controlled mica deposit.

The pegmatite consists essentially of medium- to coarse-grained quartz and [microcline] perthite, with minor amounts of muscovite and [albite] plagioclase. An area of about 400 square feet at the northern end of the pegmatite consists almost solely of coarse quartz and subhedral perthite crystals associated with books of sheet mica. The books occur clustered around the margins of the many irregular quartz pods. The books average about 3 inches in diameter, but some are 6 inches in diameter and 4 inches thick. About 20 percent of the books are wedge-shaped. The mica is colorless or very pale ruby and appears to be fairly hard. No staining of any kind was observed in the books examined.

Books of mica, slightly smaller than those described above, occur also in a fracture filling extending from the coarse quartz and perthite into medium-grained pegmatite. The vein is about 15 feet long and ½ foot wide; its attitude could not be determined.

Experience with pod and fracture-filling mica deposits has shown they are commonly sporadic in distribution and separated by considerable volumes of barren pegmatite. It seems, therefore, that this prospect could yield only small amounts of book mica per ton of rock moved.