Emerald Emerald Emerald is a gemstone and a variety of the mineral beryl (BeAl(SiO)) colored green by trace amounts of chromium and sometimes vanadium. Beryl has a hardness of 7.5–8 on the Mohs scale. Most emeralds are highly included, so their toughness (resistance to breakage) is classified as generally poor. Emerald is a cyclosilicate. The word "emerald" is derived (via and ), from Vulgar Latin: "esmaralda"/"esmaraldus", a variant of Latin "smaragdus", which originated in (smaragdos; "green gem"). Emeralds, like all colored gemstones, are graded using four basic parameters–the four "C"s of connoisseurship: "color", "clarity," "cut" and "carat weight". Normally, in the
Gemstone value of the stone. Some treatments are used widely because the resulting gem is stable, while others are not accepted most commonly because the gem color is unstable and may revert to the original tone. Heat can improve gemstone color or clarity. The heating process has been well known to gem miners and cutters for centuries, and in many stone types heating is a common practice. Most citrine is made by heating amethyst, and partial heating with a strong gradient results in “ametrine” – a stone partly amethyst and partly citrine. Aquamarine is often heated to remove yellow tones, or