The opaque gemstone known as "lapis lazuli" is a mixture of various minerals. The main component is lasurite, which gives this stone its typical shimmering blue color. Lapis lazuli usually has streaks or patches of other minerals running through it. The best quality lapis lazuli colouring is regularly distributed; Often, however, lapis lazuli is stained or striped. The stone was used as a jewelry stone in prehistoric times. Lapis lazuli was ground into powder and used as a natural, ultramarine blue pigment during the Middle Ages. Lapis lazuli is moderately difficult. The stone is sensitive to heat, perfume and cosmetics. Afghanistan is its most important source.

Luster is the most important criterion in assessing the value of a pearl. This technical term describes the reflection of light refracting on the many layers of aragonite in the mother of pearl, thus creating a glow that seems to radiate from inside the pearl. Reflected light and glow should seem as energetic and deep as possible, two qualities that are associated with a thick layer of mother-of-pearl. The value of a pearl is directly proportional to the intensity of its shine.