Nacre

(aka mother-of-pearl) is the organic crystalline substance that mollusks produce to create the interior of their shells and protect themselves from irritants and parasites by smoothing them over with this substance and eventually creating a pearl.

Pearl nacre is known for its glossy luster, brightness and subtle rainbow iridescence.

The thicker that the nacre layers are, generally the more beautiful the pearl will be. Its chances of showing sharp, highly reflective luster are increased, and its ability to refract subtle rainbow iridescence is also enhanced with thicker nacre layers.

Not only does thicker nacre layers make for more beautiful, valuable pearls: it also makes pearls incredibly strong and resilient. While pearls are easily scratched, measuring a mere 3 on the Moh’s Scale but they are amazingly strong, able to withstand surface strikes without cracking extremely well. Pearls with thick nacre layers are more durable and able to tolerate wear and tear – the thicker the nacre, the better the pearl.

Cultured Tissue-nucleated Freshwater pearls are made of 100% solid nacre; the pearl’s nucleus is just a tiny piece of donor mantle tissue, not a round mother-of-pearl bead like its saltwater cousins. As the pearl grows inside the Freshwater mollusk, the tiny square of tissue degrades inside the structure, leaving a pearl with a solid core of nacre … very much like the composition of a natural pearl.

This solid crystalline nacre make-up of Freshwater pearls make them very, very durable.

 

• How Nacre Creates Luster

Pearl nacre is a key element to make pearls valuable as a precious gemstone: Luster.

Luster gives pearls glow that appears to come from inside. Because light waves penetrate the surface layers of nacre, travel to the pearl's interior and rebounds back towards the observer, giving the viewer a bright, shiny and reflective pearl surface to admire.

Luster is graded by evaluating the details of reflected objects seen on the surface of the pearl, AND the crispness of the edges of reflected light sources visible on the pearl. The sharper and more detailed the reflected objects are, the better the luster is. Reflected light sources should have crisp, sharp edges with as little fuzziness as possible.

Different pearl types display different rates of luster, which corresponds to the average depth of nacre surrounding the internal nucleus. The tighter and more compact the nacre layers are, the faster the light return will be, creating sharper, crisper luster with defined reflections.

 

What is Orient?

Orient is a combination of luster plus iridescence. This beautiful visual phenomenon is unique to pearls, no other gemstone in the world displays orient. they may display iridescent effects, but not orient.
Additionally, not all pearls display orient. It is a rare visual effect that belongs only to the highest quality pearls.

Orient is different from the primary body color and secondary overtone colors pearls possess. For example, a pearl can have a white body color, a pink Rose overtone, and rainbow orient shifting and shimmering on top of that. This rainbow iridescence appears to float over the surface of the pearl.

How Nacre Creates Orient?

Pearls are layered with hexagonal semi-transparent aragonite platelets. many of these layers are incomplete. They are uneven and overlap each other in layer upon layer. Pearl surfaces viewed under microscopes reveal landscapes that appear almost scaly.

As we know that a single beam of light can be broken up into the seven spectral colors of the rainbow using a prism.

That’s what the nacre of pearls does.

Beams of white light hit the crystalline topography of the pearl’s surface; and most of that white light beam continues past the top layer and works its way through the pearl’s interior layers, finally hitting the solid bead nucleus inside and returning to the viewer.

But parts of that beam hit the aragonite platelets and then refracts into the seven prismatic colors of the rainbow, creating orient for the pearl’s observer.

The uneven, scaly surface layers of the pearl provides the perfect medium for breaking up light beams and refracting various colors at different color wavelengths.Each crystalline platelet acts like a miniature prism, breaking up the beam of white light into a rainbow.

The irregular compaction of the nacre layers that occurs with Free-Form Baroque shape pearls (some areas consisting of densely compacted crystal, and other areas having thinner nacre layers) have a much easier time refracting light at various wavelengths than the smoother surfaces of the perfectly symmetrical pearls and are perfect for showcasing what intense orient looks like.  encourages and enhances this iridescent effect.