Most Mint Green Quartz, also called Prasiolite, comes from one small mine in the northern Brazilian state of Minas Gerais.  The color is caused by naturally occurring radiation over millions of years.  We purchased quite a few crystals from the mine and faceted one of them into this 19x15mm oval gemstone.  It is set in a 14kt White Gold Pendant
 
For this Pendant, we recommend a 20” or 24” Medium Figaro 14kt White Gold Chain, # 1021.