Norman Muller sent this in, following my comment that I did not know of any New England examples of all quartz rock piles.There are some.
"...a quartz cairn in , on a hill above the town. This hill has a number of quartz features, such as a quartz circle near the summit (see below), and a line of quartz boulders just below it. I didn't see any quartz outcrops that could explain all this quartz, although there were small quartz boulders scattered here and there on the hillside, and I'm of the opinion that it must have been brought to the site from elsewhere. On the same hillside was a quartz cairn -- or mostly quartz -- that was some 3' high and perhaps 10-12' or so in diameter (see attached). Nearby were four small sandstone standing stones that must have some relation to the cairn."