The McEarl Mine of Arkansas is known as the pinnacle of quality for all U.S. quartz specimens. The McEarl Mine in Arkansas was originally opened in 1940, but then closed in 1943. Since then, the mines have gone through a series of reopenings and closures as various sections have "dried up". Another large crystal pocket was discovered in 1980 when a company was mining for construction material and unearthed several tons of crystals, and in 1987 another major pocket was found with what many consider to be some of the best quartz worldwide. They have this distinction due to their luster, clarity, size, sharpness and attractive striations.

Although a prismatic habit is typical of quartz, the best McEarl specimens tend to be exceptionally symmetrical and quite consistent in width throughout their bodies until the point of termination (which can often be piercingly sharp). Of all the localities in the world, it would be easy to say that a great McEarl specimen is often what people idealize and picture quartz to be, though only the best examples truly ever reach such perfection.