The mosaic is made of geometry.
The multi-material includes 3 shades, each shade consists of a mix of matte and glossy color in CoronaLayered mtl (see the screenshot of the material settings).
ATTENTION! For the FBX export file, the material is simplified and does not contain Corona Layered mtl, which is responsible for the different glossiness/mattness of the elements.

In three color variations: light, turquoise, gold.
https://sicis.belveder-e.ru/colorpedia/crystal/ 

Version Corona 9
Materials CoronaLegacyMtl
In CoronaRender versions 6 and lower, CoronaLegacyMtl=CoronaMtl

Textures and materials have logical names.
Texturing Unwrap UVW.