Pairl

Frae Wikipedia
Lowp tae: navigation, rake
Pairl
Various pairls
Various pairls
General
Category Carbonate mineral, protein
Formula
(repeating unit)
Strunz classification 05.AB
Identification
Color white, pink, siller, cream, broun, green, blue, black, yellae, orange, gowd, purpie, iridescent
Crystal seestem Orthorhombic[1]
Cleavage None[1]
Fractur Uneven
Mohs scale hairdness 2.5–4.5 [1]
Streak white
Specific gravity 2.60–2.85 [1]
Refractive index
  • Common pearl: 1.52-1.66
  • Black pearl: 1.53-1.69[1]
Birefringence 0.156
Pleochroism Absent
Dispersion None
Ultraviolet fluorescence
  • White pairls: light blue tae licht yellae;
  • Yellae an gowden pearls: yellae-green, greenish broun tae dark broun;
  • Black pairls: commonly pink tae orange-reid [2]

A pairl or purl is a haurd object produced within the saft tishie (speceefically the mantle) o a leevin shelled mollusc or anither ainimal, such as a conulariid. Juist lik the shell o a clam, a pairl is componed o calcium carbonate (mainly aragonite or a mixtur o aragonite an calcite).[3] in minute creestalline form, which haes been depositit in concentric layers.

References[eedit | eedit soorce]

  1. 1.0 1.1 1.2 1.3 1.4 Schumann, Walter (2001). Gemstones of the World. Robert Hale. p. 230. ISBN 0-7198-0301-2. 
  2. Lazzarelli, Herve Nicolas (2010). Blue Chart Gem Identification. p. 8. 
  3. "Pearl". Gemdat.org. Retrieved Aprile 3, 2017.