The largest garnet crystals in the world come out of this mountain, up to a metre across.
Gore Mountain stands near the village of North Creek in Warren County, New York, and the US Geological Survey lists the Barton Mine and Mill here as a producer of garnet. The crystals run from about 30 centimetres to a full metre in diameter, which is a size most people do not associate with a gemstone at all.
The rock is the reason. The unit that holds them is known as the Gore Mountain Garnet, a garnet amphibolite, and it is the host that let the crystals grow to that scale.
The mining began for an unglamorous purpose. In 1878 Henry Hudson Barton started taking garnet off Gore Mountain to use as abrasive on sandpaper. He went on to buy the mountain outright and founded Barton Mines on it. What he was selling was abrasive rather than gemstones, and that industrial demand is what kept the operation running.
It ran a long time and then moved. The mine on Gore Mountain operated until the early 1980s, and in 1982 the company shifted its mining to nearby Ruby Mountain. The USGS record still carries Barton Mines Corporation as the alternate name for the site.
The mountain itself is worth understanding as a piece of drainage. Its northeast slopes run into Roaring Brook and its southern slopes into Straight Brook, both of which feed North Creek. The northwest and west slopes drain the other way entirely, into the headwaters of the East Branch of the Sacandaga River and on into the Hudson.
This is a working corner of the Adirondacks rather than an open collecting ground, so treat the mine as somebody's operation and go through whatever access the company offers.
Ring ahead, because the hours move with the season.
Garnet (NY state gem)
Other places on the map within a couple of hours.