What is Diaphaneity?
Diaphaneity Optical Property in Gemstones
Diaphaneity is an optical property used to describe how much light can pass through a material without being scattered or absorbed. It refers to the degree of transparency or translucency of a substance.
A material that's transparent allows light to pass through with little or no scattering. Objects can be seen clearly through the material. Glass is transparent.
A translucent material allows some light to pass through but some is scattered or diffused. An object viewed through a material that's translucent can be seen but is blurred or obscured. An example of a translucent material is frosted glass.
An opaque material doesn't allow any light to pass through. Metal and wood are opaque.
The diaphaneity of a substance depends on its crystal structure as well as any impurities or inclusions that may be present.
Some translucent gemstones can initially appear to be opaque until they're held up towards the light.
The degree of translucency in a mineral or gemstone can vary considerably. Agate can be almost opaque to highly translucent.
Transparent and highly translucent gemstones tend to be faceted. Opaque stones or those that exhibit low translucence are often cut as cabochons.
The word "diaphaneity" comes from the Greek word "diaphanes" which means "transparent" or "clear." It's a combination of the words "dia" meaning "through" and "phaino" meaning "to show" or "to appear."
When translated the word "diaphanes" means "to show through" or "to appear through."
Over time the word "diaphaneity" was adopted into the field of mineralogy and other scientific disciplines to describe the degree of transparency or translucency of minerals, gemstones and other substances.