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Identifying Agates

Agates are rocklike gemstones composed of tiny colored quartz crystals arranged in layers. The exterior of an agate usually looks like a rock, but the interior contains multiple layers of the colored crystals. Because they are somewhat difficult to locate, agates are considered to be semiprecious gemstones. Identifying an agate can be difficult because the exterior of the stones blend in with the surrounding environment, and most types do not display any visible crystals.

Instructions

- 1
  Examine the surface color of the rock and determine whether it is a rusty red, brown or orange. These are the most popular exterior agate colors; however, agates can also be grey or white.
- 2
  Hold a stone that you think is an agate in one hand and another rock of similar size in the other hand. The agate will feel heavier because of the dense composition of quartz.
- 3
  Examine the surface of the stone for any visible banding. Banding means that there are multiple layers of different colors on the stone. These layers are usually only visible once the agate is cracked open, but agate found on beaches has sometime eroded to the point where the layers are visible from the exterior of the rock.
- 4
  Feel the exterior of the stone with your fingers to determine whether it feels silky and smooth. The rock should feel almost like a polished stone.
- 5
  Hold the stone up to the light, either sunlight or an artificial light source, and look for a translucent quality. This does not mean that the rock is see-through, only that you will be able to slightly see into the center of it. AgateLady.com describes this translucence as a waxy appearance.

Rocks & Minerals