Originally Posted by kurimja
Does anyone know if by making the gems a bit foggy/semi-opaque the LED dot of light is less obvious and more suffused??
Yes. The two ways you can diffuse a hot point is either with an opaque layer, or by using a resin with a lot of air bubbles. The gems in your reference material look like they're opaque, not crystal clear, so you'd either want to shape a sheet of acrylic sheet with a 50% opacity, pressure cast a clear resin with an added white pigment, or try various ways of diffusing the surface of the gemstone with a layer of something, like heavy sanding scratches, embedded rice paper/tissue paper, or a spray on window frosting.
I've experimented with lighting gemstones and LED covers quite a bit with mixed results.
Crystal clear gemstone and gemstone with air bubbles:
Crystal clear pressure cast gemstones with color and white pigment for opacity:
This was a project I did that used .25" opaque acryllic sheets with 50% opacity. The LEDs were directly behind the acrylic and diffused very nicely to the point where it would almost completely diffuse a hot point from the LED touching the acrylic, or even out a spot light from a distance that shone at an odd angle on more surface.
But I guess it depends on your skill level, arsenal of tools, and budget. How were you planning on making the gemstones?