Material: Peridot

"August’s birthstone, the peridot, is a light green, ancient, cosmic birthstone that has been found in volcanic lava in Hawaii—and in meteorites that have fallen to Earth. The Egyptians called peridot the “gem of the Sun” and believed it had special healing powers.
The peridot is generally a light green color. It’s a unique birthstone because it is always a shade of green and no other color. The intensity of color depends on the amount of iron; the more iron it contains, the deeper green it will be (and, generally, the more valuable). Peridot is both a day stone and a night stone, keeping its shining color even under artificial lighting. For this reason, it is sometimes called “Evening Emerald”. 
"Peridot, the bright green color of nature, is associated with harmony, good health, restful sleep, and peacefulness.  Known as the stone of compassion, peridot calms anger by giving renewal to all things.

When set in gold, this gem was said to protect the wearer from nightmares. Supposedly, it frees the mind of envious thoughts that can damage and strain relationships. Also, peridot is believed to help depression."