Emerald is a gemstone and a type of beryl (Be3Al2(SiO3)6) that has been tinted green by minute amounts of chromium or, occasionally, vanadium. The Mohs scale rates beryl's hardness as 7.5-8. The majority of emeralds are strongly included, making them generally weak in terms of toughness (resistance to breakage). Cyclosilicate is what makes emerald.
The term "emerald" comes from Vulgar Latin: esmaralda/esmaraldus, a form of Latin smaragdus, which was a via Ancient Greek: o (smáragdos; "green diamond") from a Semitic language. Old French: esmeraude and Middle English: emeraude. The term "emerald" was first used, according to Webster's Dictionary, in the 14th century.
Emeralds are rated using the four fundamental criteria—the four Cs of connoisseurship—as are other colored gemstones: color, clarity, cut, and carat weight. In grading colored gemstones, color is typically by far the most significant factor. However, clarity is ranked as a close second in the grading of emeralds. For an emerald to be regarded as a top gemstone, it must have a high degree of transparency in addition to the pure, verdant green hue specified below.
The traditional "big four" gems are sapphire, diamond, ruby, and this member of the beryl family.
The traditional "big four" gems are sapphire, diamond, ruby, and this member of the beryl family.