A thousand feet to the northeast of Middle School, on the northerly slope of the Second Watchung Mountain, a small brook begins its meandering way toward the sea. Flowing slowly northeast past Rolf's Restaurant, it passes under Stirling Rd. where it joins another brook originating near Hillcrest Rd. Plunging through the Stirling Rd. gap in Second Mountain, the brook empties into Watchung Lake. From there its waters rush into Stony Brook, Green Brook,. the Raritan River and thence to the sea. Carnelian Brook, as the stream is locally known, has been a favorite haunt of rock hounds for nearly half a century. Several hundred feet west of Rolfs, near the stream's headwaters, a marshy area has been a favorite hunting ground for carnelian and, less frequently, opal. The carnelian found there is called Touchonite. Hundreds of small pits, each a foot or two deep and two or three feet in diameter, dug over the years by mineral collectors in search of gemstones, have made the area look like a World War Two battlefield in miniature. Other rock hounds wade in the brook, stirring up the muck in hopes of spotting a stone they can add to their collection or polish for jewelry. Most carnelians found here are pebble-size; a few lucky prospectors have recovered prizes measuring two or three inches in length. Chalcedony is a variety of quartz mixed with iron and aluminum. Dark red or orange red to reddish brown chalcedony is called carnelian. Other varieties of chalcedony are onyx, bloodstone, agate and jasper. Why would a boggy stream in the Second Mountain be such an excellent source of carnelian? According to William Selden of the Rutgers Geological Museum in New Brunswick, chalcedony is formed near the surface of the earth in naturally-occurring cavities in volcanic rock. Second Mountain originated when great masses of lava flowed over the area millions of years ago. As the magma cooled. numerous openings ranging in size from microscopic spaces between grains to fissures many inches across developed. Water penetrating upward through the crust or downward from the surface dissolved soluble materials out of the rock, became mineral-laden and, near the surface, coated and filled the fissures with mineral crystals. Later, when tectonic forces uplifted the hardened lava flows, the rock fractured, exposing the embedded quartz crystals to erosion. Tens of thousands of years ago a stream began cutting its way through a large deposit of chalcedony, carrying pieces of the mineral to the low boggy area behind Rolf's where it was deposited in the sand and silt that also collected there. Because the carnelian found behind Rolf's is generally smooth, it is likely it was tumbled in the rushing waters of a much larger stream than the one that slowly courses its way through the swampy area today. The carnelian's origin may well have been many miles from its present location. Interestingly, carnelian has also been found in the small stream that meanders behind the former site of St. Mary's Church, Stony Hill. Why is the carnelian found behind Rolf's known as Touchonite -- a name, by the way, not found in any reference book on minerals? The site of Rolf's was once the location of a tavern and convenience store operated in the 1930s, 1940s and 1950s by Leon Touchon and his family. When he left business, the tavern became known as Sonny's Countryside Inn and later as Charlie Brown's. In the late 1980s the old building was demolished and replaced, further back from the road, by Rolf's. [With the assistance of John D. Farrell and Mrs. Hildegard Touchon. Mrs. Touchon owns a 11.7 oz. piece of Touchonite she found many years ago behind St. Mary's. Farrell is the proud owner of a 15.5 oz. sample found near Rolfs. |