|
|
9.
Transmitting Light Through Minerals ~ A mineral can be:
|
transparent |
|
|
clear, see right
through it when it is sliced thin |
|
|
called "gemmy",
desirable for gemstones
|
|
- quartz crystal, celestite, selenite |
|
translucent |
|
|
see shapes &
shadows through it when it is sliced thin |
|
|
chemical
impurities can cause the mineral to be cloudy
|
|
- calcite, quartz, sphalerite |
|
opaque |
|
|
can’t see light
through it at all when it is sliced thin |
|
|
rarely used for
gemstones
|
|
- metals, gypsum, |
|
