The easiest way to do gemstone therapy is to wear high quality round beads around the neck. Intention strengthens the process but is not necessary. Metal inhibits the process.
If metal surrounds the gemstone, its affects are often greatly reduced (and sometimes eliminated).
High quality gemstones are undyed, not irradiated and have very few inclusions and cracks. Beware that there are several look-alike glass and fake stones out there.
Generally, if the cracks are darker than the bead - the bead is dyed.
To determine which stone to use, I recommend going to several bead stores and seeing if any stone attracts you. Verify that the stones are not dyed and ask if the stones have been treated. String the beads on silk if possible.
Information by: Lorraine Venner