ياقوت

الياقوت حجر كريم يتراح لونه من الوردي إلى الأحمر، وهو أحد أصناف المعدن كورندم (اكسيد الألومنيوم). اللون الأحمر الشائع سببه عنصر الكروم.

Ruby
Natural ruby crystals from Winza, Tanzania
العامة
التصنيف	Oxide mineral variety
الصيغة (repeating unit)	aluminium oxide with chromium, Al2O3:Cr
النظام البلوري	Trigonal
Crystal class	Hexagonal scalenohedral (3m) H-M symbol: (3 2/m)
Space group	R3c
التعرف
Color	Near colorless through pink through all shades of red to a deep crimson
Crystal habit	Terminated tabular hexagonal prisms
Cleavage	No true cleavage
Fracture	Conchoidal, splintery
Tenacity	Brittle
Mohs scale hardness	9.0
Luster	Subadamantine, vitreous, pearly (on partings)
Streak	White
Diaphaneity	Transparent, translucent
الجاذبية النوعية	3.97 – 4.05
الصفات البصرية	Uniaxial -
Refractive index	nω=1.768–1.772 nε=1.760–1.763
Birefringence	0.008
Pleochroism	Strong: purplish-red – orangy-red
التشتت	0.018
Ultraviolet fluorescence	Red under longwave
References

وقد استخدمت بلورة ياقوت مصنَعة لإنتاج أول ليزر.

كورندم هو الياقوت عندما يشوبه كروم

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 الخصائص الطبيعية

Crystal structure of rubies

Rubies have a hardness of 9.0 on the Mohs scale of mineral hardness. Among the natural gems only moissanite and diamond are harder, with diamond having a Mohs hardness of 10.0 and moissanite falling somewhere in between corundum (ruby) and diamond in hardness. Sapphire, ruby, and pure corundum are α-alumina, the most stable form of Al₂O₃, in which 3 electrons leave each aluminum ion to join the regular octahedral group of six nearby O²⁻ ions; in pure corundum this leaves all of the aluminum ions with a very stable configuration of no unpaired electrons or unfilled energy levels, and the crystal is perfectly colorless.

Transmittance of ruby in optical and near-IR spectra. Note the two broad violet and yellow-green absorption bands and one narrow absorption band at the wavelength of 694 nm, which is the wavelength of the ruby laser.

 الياقوت مقابل الزفير الوردي

Generally, gemstone-quality corundum in all shades of red, including pink, are called rubies. However, in the United States, a minimum color saturation must be met to be called a ruby; otherwise, the stone will be called a pink sapphire. Drawing a distinction between rubies and pink sapphires is relatively new, having arisen sometime in the 20th century. Often, the distinction between ruby and pink sapphire is not clear and can be debated. As a result of the difficulty and subjectiveness of such distinctions, trade organizations such as the International Colored Gemstone Association (ICGA) have adopted the broader definition for ruby which encompasses its lighter shades, including pink.

 التواجد الطبيعي

The Mogok Valley in Upper Myanmar (Burma) was for centuries the world's main source for rubies. That region has produced some exceptional rubies, however in recent years few good rubies have been found. In central Myanmar, the area of Mong Hsu began producing rubies during the 1990s and rapidly became the world's main ruby mining area. The most recently found ruby deposit in Myanmar is in Namya (Namyazeik) located in the northern state of Kachin.

 العوامل المؤثرة على القيمة

Rubies, as with other gemstones, are graded using criteria known as the four Cs, namely color, cut, clarity and carat weight. Rubies are also evaluated on the basis of their geographic origin.

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  بلورة ياقوت متواجدة طبيعياً، قبل الصقل، طولها 2 سم.

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  Natural ruby with inclusions

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  A cut pink ruby

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  Purple rubies

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  Victorian ruby and diamond brooch

 الياقوت الإصطناعي والمقلـَّد

Artificial ruby under a normal light (top) and under a green laser light (bottom). Red light is emitted

 أرقام قياسية وياقوتات شهيرة

Rubies at the National Museum of Natural History, Washington, D.C., USA

• The Sunrise Ruby is the world's most expensive ruby, most expensive coloured gemstone, and most expensive gemstone other than a diamond. In May 2015, it sold at auction in Switzerland to an anonymous buyer for US$30 million.
• A synthetic ruby crystal became the gain medium in the world's first optical laser, conceived, designed and constructed by Theodore H. "Ted" Maiman, on the 16th of May, 1961 at Hughes Research Laboratories. The concept of electromagnetic radiation amplification through the mechanism of stimulated emission had already been successfully demonstrated in the laboratory by way of the Maser, using other materials such as ammonia and, later, ruby, but the Ruby Laser was the first device to work at optical (694.3 nm) wavelengths. Maiman's prototype laser is still in working order.

 الاشارات التاريخية والثقافية

• In Job 28:18 31 and Proverbs 3:15 31, wisdom is more valuable than rubies. In Proverbs 31:10 31, a wife of noble character is worth more than rubies.
• An early recorded transport and trading of rubies arises in the literature on the North Silk Road of China, wherein about 200 BC rubies were carried along this ancient trackway moving westward from China.
• Rubies have always been held in high esteem in Asian countries. They were used to ornament armor, scabbards, and harnesses of noblemen in India and China. Rubies were laid beneath the foundation of buildings to secure good fortune to the structure.

 انظر أيضاً

• Anyolite
• List of gemstones
• List of minerals
• Shelby Gem Factory
• Verneuil process
• قائمة المعادن

 وصلات خارجية

• International Colored Stone Association's ruby overview page
• Webmineral crystallographic and mineral info