Conch Pearl Facts
What is a Conch Pearl?
A conch pearl is a non-nacreous, calcareous concretion produced by the Queen Conch mollusk (Strombus gigas) which lives primarily in the Caribbean starting near southern Florida and extending as far as Bahamas and Grenada. Conch pearls often exhibit a flame-like pattern due to concentrically arranged calcium carbonate platelets in a lamellar fashion. Conch pearls (pronounced "konk") contain no nacre, so technically they are not actually pearls at all. Instead, the gems are calcareous concretions, similar to kidney stones in humans. Conch pearls and nacreous pearls have the same chemical composition the only difference between them is their polycrystalline structures.
Color & Flame Structure
The principal determinant of value for a conch pearl is its color as well as shape, size and flame vibrancy. Although many tend to be orange, yellow, beige or ivory, enough are pink for these pearls to have been known as "pink pearls" in the trade circa 1900. The most prized colors by collectors are anywhere from deep rose red, salmon orange to deep pink. It is believed by researchers that the conch pearl's color is based on its location within the mantle of the host animal and the age and color of the host's shell. For instance, the highly prized pink pearls are believed to grow in sexually mature pink conchs while the yellow pearls are found in young conchs that have light or golden lips of their shells. It has also been determined that the healthier their marine environment, usually close to reefs, create vibrant colors. The tones of brown, beige, tope colors being the opposite.
The unique surface quality and chatoyancy of conch pearls is referred to as its "flame structure," describing the distinctive mottled surface pattern and characteristic flicker of light across the surface. This flame structure pattern can sometimes form an 'eye,' elevating its value. Flame structure is found mostly in the salmon, pink, and red toned pearls. This significantly increases the value and price of the conch pearl.
Size, Shape & Care
Most conch pearls have an elongated, oval, or baroque shape, and near-round specimens are very rare. Conch pearls weigh significantly more than oyster pearls, with a specific gravity of 2.85; and unlike other pearls, are sized by carat weight. Conch pearls are rated harder than nacreous pearls resulting in more resistance to erosion and corrosion than nacreous pearls. Although conch pearls can be found over 100 carats, larger sizes (above 5 carats) of conch pearls are uncommon, with the average size being less than 3 carats. Due to the high value of conch pearls, drilling and/or gluing should be avoided in the mounting, as this will devalue the pearl. Known as the night gem, prolonged exposure to sunlight (ultraviolet light) can have a dulling and fading effect. Indoor lighting does not seem to have effects on the pearls. It is an organic gem, therefore, jewelry should be used with care-no gardening, rock climbing, safaris and washing dishes is also out of the question!