Chrysoprase - is the gemstone variety of Chalcedony that contains small amounts of nickel. Its color is normally apple green but can vary from lighter to darker green. Translucent stones in larger sizes are rare. Marlborough Green from Australia is a dead ringer for high end jadeite's top color and translucency, "Imperial," to "apple green," and can be very expensive with good clarity, translucency and color. Size and cut of cabochons also make price go higher. Often faked, mislabeled or treated in Asia. The famous Marlborough mines in Australia were completely exhausted by the 1970s' by high-end, luxury jewelers and in particular Van Cleef & Arpels. Collector's and miners who pocketed some of the finest rough in the 1970s' on occasion release some amazing rough in the highest quality on to the market but it is expensive.
Chalcedony - is valued for high end jewelry and you will see blue purple and green chalcedony in the jewelry lines and custom pieces produced by the finest artisan jewelers in the world. It is always cabbed and precision cabbed or carved pieces can bring high dollar. Turkish Blue is one of the finest as well as Indonesian Green if not chalky. Indonesia also produces a grape Kool-aid colored gem. Chalcedony is covered by a brown or chalky white crust in rough form and often resembles a geode. The outer areas of the gem in the Turkish Blue are the most saturated and get lighter as you fo towards the core. They often wrongly refer to the light core pieces as "opal." Large pieces of chalcedony when carved by top gem carvers can be made into elaborate lamp-bases, urns, animal/flower carvings and vases which the wealthy have purchased for hundreds of years. Chalcedony like turkish blue is often passed off as expensive lavender or blue jadeite.