Lustre (mineralogy)
Lustre (
American English:
luster) is a description of the way light interacts with the surface of a
crystal,
rock, or
mineral. For example, a
diamond is said to have an
adamantine lustre and
pyrite is said to have a
metallic lustre.
The word
lustre traces its origins back to the
Latin word
lux, meaning "light", and generally implies radiance, gloss, or brilliance.
Other descriptive terms used for gems include
vitreous, like
glass;
resinous, like
amber;
waxy, like
jade;
greasy, like
soapstone;
pearly; and
silky.
The term is also used to describe other items with a particular sheen (for example,
fabric, especially
silk and
satin, or
metals).
*
Hornblende for a description of lustrous
ores.
