Tridacna Peals

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Refractive Index : 1.685-1.530

Optical Characteristic : AGG

Specific Gravity : 2.89-2.81

Formula : Mostly CaCO3

Crystal System : Organic

Variety/Species : Tridacna Pearls

Species/Group : Calcareous concretons

Birefringence : 0.155

Dispersion : N/A

Hardness : 2.5 to 4

Toughness : Fair to poor

Ultrasonic : Never

Steam : Never

UV Long : Inert

UV Short : Inert

Pleochroism : None

Strength : N/A

Pleochroism Colors : None

Heat : sensitive

Acids : sensitive

Light : stable

Polish Luster : vitreous to dull

Fracture : Uneven

Fracture Luster : Dull

Clarity Type : N/A

Tones : N/A

Saturations : N/A

Cause of Color : None

Enhancements : None

Cleavage : None

Color Range : Pink, Yellow, orange, red, brown, pinkish, orangy, reddish, brownish, whitish

Transparency : Tranparent to opaque

Phenomena : None

Separations : Tridacna Peals from-

Identifying Characteristics and information
Very rare. They are stony growths produced by mollusks. Mottled coloring.
Distinct wavy flame-like surface structure and sheen.
Not really pearls because they lack nacre. They are made of aragonite and calcite crystals.

Spectral Data
Not diagonistic.

Trade Names and Misnomers
coconut Pearls(M)
Tridacna Pearls

Posted in Organic Gemstones