Technically known as diaphaneity, transparency refers to the way light interacts with the surface of a gemstone. There are three different levels of transparency for all objects: they are described as transparent, translucent or opaque.
Transparent objects, including gemstones, are those that allow light to enter and exit in a relatively undisturbed manner.
Translucent objects are those that allow light to enter, but disturb and distort it. To explain the difference between transparent and translucent, imagine holding an object in front of this text. If you can see through it and still read it, then it is transparent. If you can still make out that there is something behind the object, but cannot read it then it is a translucent object. If the light cannot penetrate the object, then it is said to be opaque.
If you were to hold a large Agate in front of this text, you would see nothing at all; Agate is therefore opaque. It is worth noting that some gemstones that are normally transparent, become translucent if heavily included.
