Emerald is a classic sparkling green shimmer top coat, meant for layering over other polishes. 

Rather than offering sets, purchasing three or more bottles of polish from the Gemstone collection in a single order will give a discount of 3.5% on all Gemstone collection polishes in the order, which will be reflected in the cart under the line "Gemstone collection discount."

The last photo shows what Starlight Polish 15mL and 7.5mL bottles look like.