Emerald Grades:
The best quality Emeralds are from Columbia & Brazil. Diamonds from Columbia are renowned for the highest quality though tend to have more inclusions and range between a darker or lighter green hues, therefore fewer meet the highest clarity, depth and vividness. Those that do are amongst the most expensive emeralds. Columbian emeralds account for around 80% of the world's emerald market as they are able to satisfy both the cheaper and expensive market. Brazil was home to cheaper emeralds in the 60's and used in most high street jewelers, newer mines however are producing some of the worlds best Emeralds especially from the Itabira/Nova Era belt. While the rarest and most expensive emerald is the red beryl. While chemically similar to green emeralds except for a mineral trace element which creates its red color. Red emeralds are priced equal to diamonds. East African Zimbabwe emeralds while smaller are a lovely warm and intense green while Zambia emeralds have a darker green.  All East African emeralds are rich in color and quite often found with the desirable blue-green hue. For that reason they are often found in expensive jewellery.
One of our favorites though are Indian emeralds that come from the Ajmer mines in Rajasthan. They have great clarity and a lively green hue and are often found in some of the more unique jewellery.
The finest emeralds should not be too bright or dark. A bright vivid green has no depth while a dark green has depth but no vividness.
To tell if an emerald is real, hold it up to a light and look at it closely. If it reflects the different colors of the rainbow, it isn't a real emerald.
A real emerald should have little fracture lines deep inside. But definitely not blobs or blotches.
Mined emeralds can range in price from a few $dollars to $1000's per carat depending on the colour, hue, clarity and inclusions.
Emerald mining is expensive as it can take several tons of mining to find just one small raw emerald rock.

Lab Grown Emeralds:
Man made emeralds are becoming increasingly popular even in expensive jewellery. Just like Diamonds, they can be grown from the seed of an emerald and apart from the logistics and environmental devastation of earth mined emeralds, a lab grown emerald has the best balance of clarity, colour and hue making it equal visually to the highest quality mined emerald. It is after all a 'real' emerald even to a jeweler.