Also known as haplite, aplite is an intrusive igneous rock that chiefly consists of quartz and feldspars. Fine-grained and granitic, the material is sometimes utilized in the process of glassmaking.

Aplite is light in color and exhibits a granular texture, similar to that of sugar. The rock is generally found in small masses independent from other minerals. Aplite does, however, frequently occur with pegmatite, a similar rock that is more coarsely grained. The two igneous rocks may even form thin strata, or layers, within each other and are believed to have developed at the same point in history. A relatively rare gemstone called chrysoberyl can be found in aplites and pegmatites. Composed of beryllium and aluminum oxide, chrysoberyl varies in color depending upon which optical axis is being observed, and certain varieties of the mineral form the popular cat’s-eye stones when sliced into a convex shape.