Highly valued as gemstones, emeralds are a grass-green variety of beryl. The capacity of emeralds to deflect light and to break white light into its component colors is not high, so cut stones display little brilliancy or fire (flashes of color). The color that gives this gem its value comes from the presence of small amounts of chromium. The most important production of fine-quality gem material is Colombia; emeralds are also mined in Russia, Australia, South Africa, and Zimbabwe. Synthetic emeralds are identical to natural crystals and may rival them in color and beauty.
1 One of the primary reasons why BMI is a flawed measurement tool is that it uses weight as a measure of risk, when it is actually a high percentage of body fat that makes a person obese.  Many experts are now leaning toward body fat percentage as the most accurate measure of obesity.
BMI Indications of Clinical Malnutrition. A teenage girl is getting her height measured. Photo Credit Thinkstock Images/Stockbyte/Getty Images. Because the body mass index (BMI) is an indicator of fitness, it is a useful tool for doctors in determining a personâs health.eople who are underweight have a BMI of 18.5 or lower. When a person has what is considered to be an underweight BMI, clinicians will gather other data and, together with BMI, determine whether there should be concerns regarding malnutrition.