Amphibolite (Garnet-bearing)
“Dark amphibole rock with garnet treasures”
Garnet-bearing amphibolite is a medium- to high-grade metamorphic rock rich in hornblende and plagioclase, studded with red almandine garnets that grew during metamorphism. The garnets indicate higher temperatures and pressures than plain amphibolite, marking a step deeper into the metamorphic realm.
hornblende, plagioclase, garnet (almandine), quartz, biotite, epidote, titanite
Adirondacks (New York, USA), Scottish Highlands, Black Forest (Germany), Lofoten (Norway), Gore Mountain (New York — garnet mining)
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Gore Mountain in New York's Adirondacks contains garnet amphibolite with individual garnet crystals up to 35 cm across — some of the largest garnets ever found, mined since the 1870s for industrial abrasives.
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What industrial application drove the mining of giant garnets from Gore Mountain's amphibolite?
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