Pearl

Pearl
Various pearls
Various pearls
General
CategoryCarbonate mineral, protein
Formula
(repeating unit)
Strunz classification05.AB
Crystal systemOrthorhombic[1]
Identification
Colorwhite, pink, silver, cream, brown, green, blue, black, yellow, orange, gold, purple, iridescent
CleavageNone[1]
FractureUneven
Mohs scale hardness2.5–4.5[1]
Streakwhite
Specific gravity2.60–2.85[1]
Refractive index
  • Common pearl: 1.52-1.66
  • Black pearl: 1.53-1.69[1]
Birefringence0.156
PleochroismAbsent
DispersionNone
Ultraviolet fluorescence
  • White pearls: light blue to light yellow;
  • Yellow and golden pearls: yellow-green, greenish brown to dark brown;
  • Black pearls: commonly pink to orange-red[2]
Georgian seed pearl gold ring

A pearl is a hard glistening object produced within the soft tissue (specifically the mantle) of a living shelled mollusk or another animal, such as a conulariid. Just like the shell of a mollusk, a pearl is composed of calcium carbonate (mainly aragonite or a mixture of aragonite and calcite)[3] in minute crystalline form, which has been deposited in concentric layers. The ideal pearl is perfectly round and smooth, but many other shapes, known as baroque pearls, can occur. The finest quality natural pearls have been highly valued as gemstones and objects of beauty for many centuries. Because of this, pearl has become a metaphor for something rare, fine, admirable and valuable.

The most valuable pearls occur spontaneously in the wild, but are extremely rare. These wild pearls are referred to as natural pearls. Cultured or farmed pearls from pearl oysters and freshwater mussels make up the majority of those currently sold. Imitation pearls are also widely sold in inexpensive jewelry, but the quality of their iridescence is usually very poor and is easily distinguished from that of genuine pearls. Pearls have been harvested and cultivated primarily for use in jewelry, but in the past were also used to adorn clothing. They have also been crushed and used in cosmetics, medicines and paint formulations.

Whether wild or cultured, gem-quality pearls are almost always nacreous and iridescent, like the interior of the shell that produces them. However, almost all species of shelled mollusks are capable of producing pearls (technically "calcareous concretions") of lesser shine or less spherical shape. Although these may also be legitimately referred to as "pearls" by gemological labs and also under U.S. Federal Trade Commission rules,[4] and are formed in the same way, most of them have no value except as curiosities.

Etymology

The English word pearl comes from the French perle, originally from the Latin perna meaning leg, after the ham- or mutton leg-shaped bivalve.[5]

Other Languages
Alemannisch: Perle
العربية: لؤلؤ
অসমীয়া: মুকুতা
asturianu: Perlla
Avañe'ẽ: Itaveratĩ
azərbaycanca: Mirvari
বাংলা: মুক্তা
беларуская: Жэмчуг
беларуская (тарашкевіца)‎: Жэмчуг
български: Перла
català: Perla
čeština: Perla
Cymraeg: Perl
dansk: Perle
Deutsch: Perle
eesti: Pärl
Ελληνικά: Μαργαριτάρι
español: Perla
Esperanto: Perlo (globeto)
euskara: Perla
فارسی: مروارید
français: Perle
galego: Perla
客家語/Hak-kâ-ngî: Chṳ̂n-chû
한국어: 진주
հայերեն: Մարգարիտ
हिन्दी: मोती
hrvatski: Biser
Ido: Perlo
Bahasa Indonesia: Mutiara
italiano: Perla
עברית: פנינה
Basa Jawa: Mutyara
ქართული: მარგალიტი
қазақша: Маржан
коми: Вӧсь
Latina: Margarita
latviešu: Pērle
lietuvių: Perlas
Limburgs: Paerel
magyar: Igazgyöngy
मैथिली: मोती
македонски: Бисер
മലയാളം: മുത്ത്
मराठी: मोती
مصرى: لؤلؤ
Bahasa Melayu: Mutiara
монгол: Сувд
မြန်မာဘာသာ: ပုလဲ
Nederlands: Parel
日本語: 真珠
norsk: Perle
norsk nynorsk: Perle
occitan: Pèrla
oʻzbekcha/ўзбекча: Dur
ਪੰਜਾਬੀ: ਮੋਤੀ
پنجابی: موتی
پښتو: مرغلره
polski: Perła
português: Pérola
română: Perlă
русский: Жемчуг
саха тыла: Чөмчүүк
संस्कृतम्: मुक्ता
Scots: Pairl
sicilianu: Perna
සිංහල: මුතු
Simple English: Pearl
سنڌي: موتي
slovenčina: Perla
slovenščina: Biser
српски / srpski: Бисер
srpskohrvatski / српскохрватски: Biser
suomi: Helmi
svenska: Pärla
Tagalog: Perlas
தமிழ்: முத்து
తెలుగు: ముత్యము
тоҷикӣ: Гавҳар
Türkçe: İnci
українська: Перли
اردو: موتی
vèneto: Margarita
Tiếng Việt: Ngọc trai
ייִדיש: פערל
粵語: 珍珠
žemaitėška: Žemčiūgs
中文: 珍珠