The finest lapis for jewelry has been a pure deep blue color without any pyrite (gold looking streaks) or calcite showing. However, many people like their lapis with pyrite flecks or streaks that add interest. Calcite is a softer material than lapis and prevents a high polish when found mixed in the lapis matrix. This material is considered a lower quality and is less expensive than evenly colored blue lapis. In the hands of an artist, lapis is capable of producing wonderful carvings. It takes a good polish and is generally trouble free when used in jewelry settings.