The materials used to create the pieces are mosthly :
What is a semi-precious stone?
A semi-precious stone is a gemstone.
A gemstone is a mineral, rock (such in the case of lapis lazuli), or petrified material that when cut or faceted and polished is collectible or can be used in jewelry. Others are organic (such as amber, which is fossilised tree resin, and jet, a form of coal). Some gemstones which may be generally considered precious or beautiful are too soft or too fragile to be used in jewelry (for example, single-crystal rhodochrosite) but are exhibited in museums and are sought by collectors.
The semi-precious stones that I use come mainly from Czech Republic and Europe. I am in the process of exploring and buying beads here in Mexico.