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SWP-Strang,2,5-3,0mm,fl.,rd,AA+ - 1 Stück

Item number GO80152025
1 piece

available, in stock

Pearls are produced by shells, rarely also by snails. If a sandkorn or a parasite penetrates into the inside, soft tissue of the shell, this encases the foreign body with layers of aragonite (calcium carbonate) and conchyn (organic horn substance). The gloss of the pearl, called luster or orient, results from interference of the light, which is reflected on the boundary surfaces of the shell layers. Due to the great demand of pearls, some kinds of shells are cultivated at pearl farms on the sea or in fresh water lakes, in order to get cultivated pearls. There is a difference between sea water cultured pearls (e.g. Akoya) and fresh water cultivated pearls. In order to get a cultivated pearl, a nacre ball encased with epithelium is inserted into the shell (usually, only a epithelium core for fresh water cultivated pearls). Thus it is possible for the shells to form larger pearls in a shorter time. Pearls are classified acc. to roundness, color, surface, lustre and size.
Physical data:
    Color: white, pink, silver -, cream -, gold-colored, green, blue,black;
    Stroke color: white;
    Mohs hardness: 21/2-41/2;
    Density: 2.60-2.85;
    Fissionability: none;
    Fracture: uneven;
    Crystals: prismatic, micro-crystalline;
    Chemism: calcium-carbonate + organic substance + water;
    Transparency: translucent, opaque;
    Refraction: 1.52-1.66, black pearls 1.53-1.69;
    Birefringence: - 0.156;
    Dispersion: none;
    Fluorescence: marine pearls weak, natural black pearls red to reddish, river pearls strong pale-green.

(also cultivated pearls, fresh water and sea water pearls)
Strands
Quality AA+
approx. 40 cm
lilac
round
ø 2.50-3.00 mm