An extremely rare coloration, pearl mainly shows up in horses with Spanish origins. The color occurs due to a dilution gene known as the “barlink factor” which lightens the horse’s base color.

color, luster, surface quality, nacre quality, and—for jewelry with two or more pearls—matching. Size: When other value factors are equal, larger pearls are rarer and more valuable than smaller pearls ...

color, luster, surface quality, nacre quality, and—for jewelry with two or more pearls—matching. Size: When other value factors are equal, larger pearls are rarer and more valuable than smaller pearls ...

Rare freshwater pearl mussels have been found in Scottish lochs for the first time, according to researchers The critically endangered species had only previously been known to live in rivers ...

Sky-gazers across Scotland were treated to a rare sight on Sunday ... and with their shimmering colours they are often referred to as "mother-of-pearl". One BBC Weather Watcher said "absolutely ...

Opinions expressed by Forbes Contributors are their own. I cover upmarket jewelry, timepieces & ethical, sustainable jewelry. Glowing like sunlight made solid, this 13-15mm golden South Sea pearl ...