The modern birthstone for August is
Peridot. Peridot is gem-quality forsteritic olivine. Olivine is very abundant mineral, but gem quality peridot is rather rare. Peridot is one of the few gemstones that occur in only one color: basically an olive green. The intensity and tint of the green however depends on how much iron is contained in the crystal structure, so the color of individual peridot gems can vary from yellow-green through olive green to brownish green. The most valuable is considered a dark-olive green color. Peridot leads you to discover your higher self through perseverance and determination!
The traditional birthstones for August are
Sardonyx &
Carnelian.
Sard is a brownish mineral, and when it forms together with the straight white bands of onyx, the resulting stone is called Sardonyx. Sardonyx is a banded variety of chalcedony which is cryptocrystalline quartz. Sardonyx can be black with white bands or orange-red with white bands. It is said to increase courage and eloquence.
Carnelian Agate is also a variety of the silica mineral chalcedony colored by impurities of iron oxide. The color can vary greatly, ranging from pale orange to an intense almost-black coloration. The word carnelian is derived from the Latin word caro, carnis meaning flesh, in reference to the flesh color sometimes exhibited. Carnelian is said to assist in stimulating creativity. It seems to have a clearing effect, dispelling negative energies as it replaces them with positive ones.