granite minimum

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granite minimum In the ternary system quartzalbiteorthoclase, the common low-temperature point marking either the last of a melt to crystallize after fractional crystallization has occurred, or, conversely, the first fraction of any solid mixture of alkali feldspars and quartz to melt upon heating. As this liquid has a very similar composition to many granites, the temperature point at which it forms is known as the granite minimum.