This ancient rock, known to be used for ornamentation and dyes dates back as early as 7570 BC, is an aggregate of several minerals. The three major minerals that comprise lapis are lazurite, calcite, and pyrite. Lazurite is the ingredient responsible for producing the gem’s most prized color—bright royal blue. Calcites presence can appear as white layers or mottling and can also be finely intermixed with lazurite to produce a rock with a faded denim color. Pyrite usually occurs in lapis lazuli as tiny, randomly spaced grains with a contrasting gold color.
As a general rule, solid blue lapis or solid blue with a few grains of gold pyrite are the most desirable colors, however, desirability varies from stone to stone and from person to person. Lapis is a softer stone (Mohs scale 5) but takes a great polish, perfect for beads or pendants that are not suspectable to harsh abrasion.