Lantern Hill owes its prominence to a mass of tough, pure quartz, a mineral similar to window glass composed of silicon and oxygen. Minerals are to rocks what ingredients are to cookies; and quartz, like sugar, is a very common ingredient. But the rock of Lantern Hill has only the sugar; it is a one-mineral rock. Although quartz is a very common mineral, it is rarely found in such a large and pure deposit. The size, purity, and case of extraction of the Lantern Hill deposit - in addition to good marketing - has allowed the Lantern Hill operation to continue where other mines have failed. In the past, the quartz has been crushed and sold for use in wood filler, tooth powder, hand soap, foundry sand, and thermos bottles. Current uses for crushed Lantern Hill quartz include building stone aggregate, gravel roofs, swimming pool filters, and aquarium gravel.

The most widely mined deposit in the Uplands was a rock known as pegmatite. Hundreds of pegmatites of all sizes have been identified in the state, from narrow bands only a few inches across to thick layers tens of yards wide. Pegmatite is similar in composition to granite, except that the individual crystals are much larger, sometimes as much as three to four feet long. When one holds a hunk of pegmatite in hand, it looks like a piece of granite viewed through a magnifying glass. It is a very striking rock, either pink or white in color. Several bands of pegmatite can be seen on Route 9 in Deep River where they cut dramatically across the roadcuts between Exits 3 and 4. The large size of the mineral crystals and the occasional inclusion of precious and semiprecious gems gives pegmatites their value. The big crystals of quartz, mica, and feldspar are easily separated out of the rock, simplifying the purification process so important in any mining operation. Among the gems taken out of pegmatites are beryl, aquamarine, emerald, and tourmaline. But of the dozens of pegmatite mines opened in the state, only a few located in the Middletown-Portland area are still being worked. The Feldspar Corporation runs all of these quarries, producing feldspar for making glass and ceramics, and mica for use in wallboard compound.

Granite, too, has been quarried at a number of locations in the state. Most of the important quarries were in the Coastal Slope of Eastern Connecticut: Branford, Stony Creek, Guilford, Waterford, and

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