A period is a bleed from the womb (uterus) that is released through the vagina. It happens approximately every 28 days, although anywhere between 24 and 35 days is common. Periods can begin when girls are between 8 and 16 years old, but usually start around the age of 12.
Emerald is a gemstone and a variety of the mineral beryl (Be3Al2(SiO3)6) colored green by trace amounts of chromium and sometimes vanadium. Beryl has a hardness of 7.5â8 on the Mohs scale. Most emeralds are highly included, so their toughness (resistance to breakage) is classified as generally poor.
Chemical Composition of Emerald Gemstone Panna. Emerald Gemstone is made of mineral Beryl. The chemical composition of Emerald Gemstone is Be 3 Al 2 (SiO 3) 6. Its exact magnitude is 2.67 â 2.78 and refractive index series is 1.566 â 1.602. Emeraldâs hardness on Mohs scale is 7.5 â 8.0. Table is shown below â