Which set of gemstones are among those that often form in pegmatites?

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Study for the DCA Gemology Test. Utilize flashcards and multiple-choice questions, each question offering hints and explanations. Prepare effectively for your exam with confidence!

Multiple Choice

Which set of gemstones are among those that often form in pegmatites?

Explanation:
Pegmatites crystallize from granitic melts with a lot of water and other volatiles, which lets crystals grow very large and concentrates minerals that are difficult to form in ordinary rocks. That environment favors gemstone-forming minerals such as amethyst and citrine (varieties of quartz), aquamarine (beryl), chrysoberyl, moonstone (a feldspar variety), tourmaline, topaz, and spessartine garnet. This set includes many of the classic pegmatite gemstones, making it the best match. The other options mix stones that aren’t as characteristically tied to pegmatites, or list common rock-forming minerals rather than gemstone-quality varieties.

Pegmatites crystallize from granitic melts with a lot of water and other volatiles, which lets crystals grow very large and concentrates minerals that are difficult to form in ordinary rocks. That environment favors gemstone-forming minerals such as amethyst and citrine (varieties of quartz), aquamarine (beryl), chrysoberyl, moonstone (a feldspar variety), tourmaline, topaz, and spessartine garnet. This set includes many of the classic pegmatite gemstones, making it the best match. The other options mix stones that aren’t as characteristically tied to pegmatites, or list common rock-forming minerals rather than gemstone-quality varieties.

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