Emerald. May birthstone.
Emerald, the birthstone for May, has been beloved for millennia, evoking rebirth and renewal.
Emerald is the most precious stone in the beryl group. The emerald name comes from the Greek "smaragdos" through the old French "esmeralde", and really means "green precious stone. It is not surprising then that the emerald is classified as one of the four traditional gemstones along with sapphire, ruby and diamond.
Technically, the emerald is a variety of beryl whose color is due to the presence of chromium and / or vanadium.
The almost opaque emerald is relatively common and is found in many countries, but its value is currently very limited. The gem quality emerald should be transparent, although it is almost never free of inclusions and internal imperfections, the so-called "emerald garden", and it is much rarer.
Today, it's the gemstone usually given as gift in the USA for the 20th and 35th wedding anniversaries.