寶玉石學第六章6[1].1紅藍寶石

1、Chapter 6 Colored Gemstones陳炳輝陳炳輝Dr. Chen BinghuiDepartment of Earth SciencesSun Yat-sen University紅寶石和藍寶石紅寶石和藍寶石Sec.6.1 RUBY & SAPPHIRESec.6.1 RUBY & SAPPHIRECONTENTS 概述概述 Introduction 性質性質 Properties 鑒定鑒定 Identification 評價評價 Appraisal 產地產地 Localities 商貿行情商貿行情 Trading一、一、概述概述 Introduction W

2、hat do you know about Corundum?Ruby is red, gem-quality corundum紅寶石的歷史和傳說紅寶石的歷史和傳說 紅寶石的紅色象征著火一樣的熱情和忠貞。紅寶石的紅色象征著火一樣的熱情和忠貞。古希臘人認為鮮紅的紅寶石能夠熔化石蠟，古希臘人認為鮮紅的紅寶石能夠熔化石蠟，并會留下印痕。他們相信紅寶石內存在巨并會留下印痕。他們相信紅寶石內存在巨大的力量，將它裝在建筑物上可避雷雨襲大的力量，將它裝在建筑物上可避雷雨襲擊。擊。 有人說紅寶石的紅色是寶石內燃燒著永不有人說紅寶石的紅色是寶石內燃燒著永不熄滅的火焰，這種火焰不會被遮擋，能透熄滅的火焰，這種火焰

3、不會被遮擋，能透過衣服，照到人的心中。過衣服，照到人的心中。 自古以來，紅寶石總是作為戀人送給自己自古以來，紅寶石總是作為戀人送給自己親愛人的定情信物。親愛人的定情信物。古代關于紅寶石還有許許多多的傳說，有一種古代關于紅寶石還有許許多多的傳說，有一種傳說認為，戴紅寶石的人會健康長壽，發(fā)財致傳說認為，戴紅寶石的人會健康長壽，發(fā)財致富，聰明智慧，愛情幸福美滿，左手戴上紅寶富，聰明智慧，愛情幸福美滿，左手戴上紅寶石戒指就有逢兇化吉、變敵為友的魔力。石戒指就有逢兇化吉、變敵為友的魔力。圣經說過，紅寶石象征著猶太部落。亞淪法衣圣經說過，紅寶石象征著猶太部落。亞淪法衣上第四粒寶石就是紅寶石上第四粒寶石就是

4、紅寶石.自從猶太人宣布建立自從猶太人宣布建立以色列王位以來，這顆珍貴的寶石一直是皇冠以色列王位以來，這顆珍貴的寶石一直是皇冠上的寵物。上的寵物。緬甸人非常珍視紅寶石，相信紅寶石能保護人緬甸人非常珍視紅寶石，相信紅寶石能保護人不受傷害。為此緬甸武士在身上割一個小口，不受傷害。為此緬甸武士在身上割一個小口，把紅寶石嵌進去，認為這樣就會刀槍不入。把紅寶石嵌進去，認為這樣就會刀槍不入。The largest known gem-quality ruby-at 250 carats-is on the crown, ordered in 1346 by Charles IV of Luxembourg,

5、 king of Bohemia (1316-78), for the shrine containing the skull of Saint Wenceslas, duke of Bohemia (921-29). A few rubies have distinguished themselves because of their size or extraordinary beauty and arc being guarded for posterity. The Louvre in Paris houses the Anne of Brittany Ruby, a 105-cara

6、t polished but irregular gem. The 167-carat Edwardes Ruby was donated to the British Museum of Natural History in 1887 by John Ruskin. This 167-carat gem was named in honor of Major-General Sir Herbert Benjamin Edwardes (1819-G8) who saved British rule in India during the years of the Indian Mutiny.

7、 Two star rubies are displayed in American museums. The Smithsonian displays the 137-carat Rosser Reeves Ruby, and The American Museum of Natural History has the 100-carat Edith Haggin de Long Ruby.Famous Rubies著名紅寶石 據稱迄今世界上唯一的特大型紅寶石重達3450克拉，是在緬甸發(fā)現的。 1983年，印度維代拉吉律師在其父母房內發(fā)現兩粒巨大紅寶石，這兩粒紅寶石包在一層煙灰之中經歷了幾個

8、世紀。維代拉吉是14一16世紀統(tǒng)治印度南部的王公的直系后裔。如今，這稀世珍寶存放在銀行之中，估計價值最少值5億美元。據記載，世界上最大的據記載，世界上最大的“鴿血紅鴿血紅”紅寶石重紅寶石重55克拉。還克拉。還有一粒有一粒“和平紅寶石和平紅寶石”重重45克拉，是第一次世界大戰(zhàn)期克拉，是第一次世界大戰(zhàn)期間在緬甸發(fā)現的，當時這粒未經琢磨的紅寶石被人以間在緬甸發(fā)現的，當時這粒未經琢磨的紅寶石被人以22500英鎊買走。英鎊買走。曾一度為曾一度為16世紀莫臥爾皇帝頭巾上飾物的阿格拉粉紅世紀莫臥爾皇帝頭巾上飾物的阿格拉粉紅寶石，重寶石，重3克拉，于克拉，于1990年年6月月20日以日以402萬英鎊的創(chuàng)萬英鎊

9、的創(chuàng)紀錄高價賣給了一位香港珠寶商，據說這是世界上第紀錄高價賣給了一位香港珠寶商，據說這是世界上第七大的粉紅寶石。七大的粉紅寶石。倫敦大英博物館中有一粒紅寶石晶體，重倫敦大英博物館中有一粒紅寶石晶體，重690克拉，克拉，產自緬甸。產自緬甸。美國自然歷史博物館中保存一粒重量美國自然歷史博物館中保存一粒重量100克拉的星光克拉的星光紅寶石（名為紅寶石（名為Edith Haggin delong）。）。 Only recent technology has enabled us to definitively distinguish ruby from its colorful twins. Thro

10、ughout history, other red gems such as spinel and garnet were mistaken for ruby. In fact, most large historical red stones (several hundred carats) are spinels. The French and Russian crowns and the Iranian treasury all contain some of the worlds largest, most beautiful ruby spinel, itself a rare ge

11、m. Recently, rubies have been grown in the laboratory. Although these grown rubies are essentially of identical composition, hardness, and brilliance to natural rubies, they have aroused some controversy. Their presence of the market is still more limited than lab-grown emeralds, however. When buyin

12、g star rubies, look for a star that has straight legs that are all of equal clarity. In addition to its place as Julys birthstone, ruby is also a recommended gift for couples celebrating their 15th or 40th wedding anniversary. Origin of NameAt one time any blue gem material was called sapphire. Refe

13、rences to a blue-flecked stone led mineral experts to realize that some of what had been called sappheiros was actually lapis lazuli. Sappheiros is Greek for blue. From the Mountains of KashmirThe finest sapphire color is rich, velvety cornflower blue. This is called kashmir out of deference to the

14、traditional source of the finest quality. Today, however, the Kashmir area of India is not generally mined because of its physical inaccessibility. Most current production comes from Sri Lanka, Burma, Thailand, Montana, Australia and Africa. Blue as the perfect sky, sapphires have been used as prote

15、ctive talismans talisman (護身符護身符) for centuries. Sapphire, sister to ruby, is known in the mineral world as corundum, which is a crystal structure composed of aluminum oxide. On the Mohs scale of hardness, sapphire ranks 9, the highest in the gem world after diamond. It is considered very durable, a

16、 great choice for rings and bracelets that are prone to knocks. Although sapphire is not as brilliant as diamond, it has striking luster.Like ruby, sapphire may be found in a translucent variety that may display a six-rayed star effect when cut into a cabochon (dome) shape. This type is known as sta

17、r sapphire, of which there are numerous synthetics on the market.Star SapphiresThe Sinhalese believed the star sapphire would protect them against witchcraft. The three intersecting rays were thought to represent faith, hope and destiny. Museums the world over exhibit star sapphires that are notewor

18、thy for size or duality. The 543-carat Star of India resides in the Morgan-Tiffany Collection in the American Museum of Natural History in New York city. 命運之石命運之石星光藍寶石星光藍寶石（忠誠、希望、博愛）（忠誠、希望、博愛）世界之最及著名寶石：世界之最及著名寶石：19kg 斯里蘭卡斯里蘭卡2302ct 澳大利亞昆士蘭澳大利亞昆士蘭 印度之星印度之星(藍色）藍色） 563ct黃色藍寶石黃色藍寶石 100ct, 斯里斯里蘭卡蘭卡 九月份的生

19、辰石、結婚九月份的生辰石、結婚45周年紀念石周年紀念石 二、性質二、性質 PropertiesChemical Formula: Al2O3, Aluminum OxideCrystal System：trigonalCrystal Habits include sapphires typical six-sided barrel shape that may taper into a pyramid, and rubys hexagonal prisms and blades. Cleavage is absent, although there is parting which occur

20、s in three directions. Fracture is conchoidal. Color is highly variable. The color can be white or colorless, blue, red, yellow, green, brown, purple, and pink; there are also instance of color zonation. Luster：vitreous Transparency: Crystals are transparent to translucent. Dichromism.主要識別特征主要識別特征常見

21、色帶常見色帶二色性強二色性強折射率：折射率：1.761.78（大多數為（大多數為1.7621.770）三、鑒定三、鑒定 Identification2、不同產地紅寶石的特征緬甸抹谷紅寶石（緬甸抹谷紅寶石（MOGOKMOGOK） 顏色：鮮明但不均勻顏色：鮮明但不均勻 包裹體：絹絲狀金紅石及粒狀礦物包裹體：絹絲狀金紅石及粒狀礦物泰國尖竹紋紅寶石泰國尖竹紋紅寶石 顏色：帶褐的紅色顏色：帶褐的紅色 包裹體：常見指紋狀包體，不見絹絲狀金紅石包體包裹體：常見指紋狀包體，不見絹絲狀金紅石包體斯里蘭卡紅寶石斯里蘭卡紅寶石 特點與抹谷紅寶石相似，但色較淺。特點與抹谷紅寶石相似，但色較淺。 含粗粒針狀金紅石、鋯石

22、暈圈含粗粒針狀金紅石、鋯石暈圈 緬甸蒙素（緬甸蒙素（MONG HSUMONG HSU）紅寶石紅寶石顏色：色較暗，透明度較差顏色：色較暗，透明度較差包裹體：云霧狀，長針狀軟水鋁石，極少量金紅包裹體：云霧狀，長針狀軟水鋁石，極少量金紅石及粒狀礦物石及粒狀礦物常見熱處理的產物（指紋狀包體）常見熱處理的產物（指紋狀包體）3、不同產地藍寶石的特征、不同產地藍寶石的特征緬甸、斯里蘭卡、印度緬甸、斯里蘭卡、印度顏色較鮮艷顏色較鮮艷含絹絲狀金紅石和指紋狀包裹體含絹絲狀金紅石和指紋狀包裹體澳大利亞、泰國、中國澳大利亞、泰國、中國顏色較暗顏色較暗刻面反光效果較差刻面反光效果較差4、合成紅藍寶石的方法及特征、合成紅

23、藍寶石的方法及特征焰熔法（維爾納葉法，焰熔法（維爾納葉法，VERNEUIL)顏色：鮮艷顏色：鮮艷二色性：常在臺面可見二色性：常在臺面可見包裹體：較干凈，可見氣泡及彎曲生長線包裹體：較干凈，可見氣泡及彎曲生長線助熔劑（助熔劑（FLUX-MELTING）Kashan, Chathorm, Inamori, Ramaura金屬片：金屬片：Pt溶劑液滴溶劑液滴窗紗狀包裹體窗紗狀包裹體水熱法（水熱法（HYDROTHERMAL）似天然寶石特征，但無晶體包體似天然寶石特征，但無晶體包體5、紅寶石與模仿品的區(qū)別、紅寶石與模仿品的區(qū)別寶石名稱寶石名稱硬度硬度相對密度相對密度折射率折射率雙折射率雙折射率多色性多色

24、性紅寶石紅寶石9 93.993.991 . 7 61 . 7 6 1.781.780.0080.008二色性強二色性強鋯石鋯石7.57.54.74.71 . 9 21 . 9 2 1.981.980.0590.059二色性中二色性中尖晶石尖晶石8 83 . 6 03 . 6 0 3.633.631 . 7 11 . 7 1 1.731.73單折射單折射無無鎂鋁榴石鎂鋁榴石7.57.53.73.73.93.91 . 7 41 . 7 4 1.761.76單折射單折射無無碧璽碧璽7 73.053.051 . 6 21 . 6 2 1.641.640.0180.018二色性強二色性強紅色玻璃紅色玻璃

25、5 56 62.32.31 . 4 01 . 4 0 1.601.60單折射單折射無無區(qū)別方法：區(qū)別方法：（1） 尖晶石、鎂鋁榴石和紅色玻璃根據其無尖晶石、鎂鋁榴石和紅色玻璃根據其無二色性，可以與紅寶石區(qū)別；二色性，可以與紅寶石區(qū)別；（2） 紅色鋯石和碧璽的雙折射率大，在十倍紅色鋯石和碧璽的雙折射率大，在十倍鏡下透過臺面可見底部棱邊的明顯雙影現象，鏡下透過臺面可見底部棱邊的明顯雙影現象，據此可以與紅寶石區(qū)別。據此可以與紅寶石區(qū)別。6、藍寶石與外觀相似寶石的識別、藍寶石與外觀相似寶石的識別寶石名稱寶石名稱硬度硬度相對密度相對密度折射率折射率雙折射率雙折射率多色性多色性藍寶石藍寶石93.991 .

26、 7 6 1.780.008二色性強二色性強尖晶石尖晶石83 . 6 0 3.631 . 7 1 1.73單折射單折射無無碧璽碧璽73.051 . 6 2 1.640.020二色性強二色性強坦桑石坦桑石6.53.351 . 6 9 1.700.009三色性強三色性強堇青石堇青石72.591 . 5 3 1.560.009三色性強三色性強藍晶石藍晶石463.691 . 7 1 1.730.016二色性中二色性中藍色玻璃藍色玻璃562.32.51 . 4 0 1.60單折射單折射無無 識別方法：識別方法：藍色尖晶石和藍色玻璃根據其無二色性，可藍色尖晶石和藍色玻璃根據其無二色性，可以與藍寶石區(qū)別；以

27、與藍寶石區(qū)別；藍色碧璽和藍晶石（市場上較少見）的雙折藍色碧璽和藍晶石（市場上較少見）的雙折射率大，在十倍鏡下透過臺面可見底部棱邊射率大，在十倍鏡下透過臺面可見底部棱邊的明顯雙影現象，據此可以與藍寶石區(qū)別。的明顯雙影現象，據此可以與藍寶石區(qū)別。坦桑石和堇青石具三色性，而藍寶石只有二坦桑石和堇青石具三色性，而藍寶石只有二色性，據此可區(qū)別。色性，據此可區(qū)別。市場上常見坦桑石往往經過熱處理，熱處理市場上常見坦桑石往往經過熱處理，熱處理后其三色性不明顯，常只有二色性。這樣可后其三色性不明顯，常只有二色性。這樣可根據二色性的顏色特征及其他性質如折射率根據二色性的顏色特征及其他性質如折射率等來識別。等來識別

28、。6、紅藍寶石的處理及識別、紅藍寶石的處理及識別處理方法處理方法 結果結果 識別識別 熱處理（優(yōu)化）熱處理（優(yōu)化） 改進顏色改進顏色 增加透明度增加透明度 去除或加強星光去除或加強星光 應力紋應力紋 針狀包裹體變?yōu)辄c線狀針狀包裹體變?yōu)辄c線狀 色團、色帶、生長紋擴散色團、色帶、生長紋擴散 晶體包裹體圓化晶體包裹體圓化 卡脖子狀次生氣液包裹體卡脖子狀次生氣液包裹體 表面擴散表面擴散 使無色藍寶石變?yōu)樗枰篃o色藍寶石變?yōu)樗枰念伾ㄗ畛Ｒ姙樗{色，也的顏色（最常見為藍色，也有紅色）有紅色） 浸入二碘甲烷中，顏色分布限于刻面棱和腰浸入二碘甲烷中，顏色分布限于刻面棱和腰棱，呈“蛛網”狀分布；或中間無色

29、，外圍棱，呈“蛛網”狀分布；或中間無色，外圍呈色圈呈色圈 充填處理充填處理 注油、 注有色膠、 注玻璃等；注油、 注有色膠、 注玻璃等； 充填助溶劑（如硼酸鹽）后充填助溶劑（如硼酸鹽）后再加熱處理（紅寶石）再加熱處理（紅寶石） 充填位置可見光暈效應；充填位置可見光暈效應； 充填助溶劑后再加熱處理的紅寶石在充填位充填助溶劑后再加熱處理的紅寶石在充填位置有助溶劑法合成紅寶石某些包裹體的特征置有助溶劑法合成紅寶石某些包裹體的特征 加色處理加色處理 將染料加入寶石中的裂理、將染料加入寶石中的裂理、裂隙中，使寶石著色裂隙中，使寶石著色 顏色在裂理、裂隙處較深顏色在裂理、裂隙處較深 復合石復合石 色差的天

30、然寶石作冠部，鮮色差的天然寶石作冠部，鮮艷合成寶石作亭部，粘合而艷合成寶石作亭部，粘合而成成 從側面觀察，顏色有別；從側面觀察，顏色有別； 成層氣泡存在（結合部）成層氣泡存在（結合部） Perfect natural gems-in color and appearance-are very rare and expensive. Controlled heating is commonly used in the trade to produce, intensify or lighten color and/or improve clarity. This allows the trade

31、 to bring more, better quality gems to the market. Heat enhancement is permanent and stable. You can clean treated or untreated rubies the same- with soapy water or a gentle commercial solvent and a brush. Mechanical cleaners are also safe, except with heavily included gems. Some rubies have fissure

32、s that break the surface and are filled with a glass-like byproduct from the heating process. Surface cavities in rubies are also intentionally filled with such material as glass, solidified borax or similar colorless substances to improve its durability and appearance. These enhancements may wear o

33、ver time if treated harshly or exposed to strong abrasives and solvents, as well as heat. The filler material used is fragile and may fall out, break or abrade. It is important to buy fine ruby from a reputable retailer who will provide, in writing, all pertinent information egarding the gem includi

34、ng enhancements and special care notes. Treatment寶石寶石生長紋及色帶生長紋及色帶熒光性熒光性包裹體包裹體其他其他天然寶石天然寶石多具色帶及色點，多具色帶及色點，色帶平直，生長色帶平直，生長紋平直、呈六邊紋平直、呈六邊形形因產地不同而不因產地不同而不同，一般呈淺同，一般呈淺中等紅色中等紅色晶體包裹體晶體包裹體熔體及氣液包裹熔體及氣液包裹體體指紋狀包裹體指紋狀包裹體大粒、色佳、大粒、色佳、質好、無裂者質好、無裂者少見少見焰熔法合焰熔法合成寶石成寶石弧形生長紋，對弧形生長紋，對小粒寶石而言，小粒寶石而言，近于平直近于平直短波紫外下呈強短波紫外下呈強橙

35、紅熒光橙紅熒光氣泡氣泡殘留不熔物殘留不熔物色佳，大多數色佳，大多數透明度好透明度好助熔劑法助熔劑法合成寶石合成寶石具平直色帶及生具平直色帶及生長紋長紋短波紫外下呈黃短波紫外下呈黃綠色熒光或中綠色熒光或中強紅熒光強紅熒光羽狀體羽狀體; 熔劑小熔劑小滴滴鉑片晶鉑片晶; 兩相包兩相包裹體裹體針狀包裹體針狀包裹體 水熱法合水熱法合成紅寶石成紅寶石可有六邊形生長可有六邊形生長色帶色帶短 波 紫 外 下 呈短 波 紫 外 下 呈中中強熒光強熒光熔體包裹體熔體包裹體; 氣氣液相包裹體液相包裹體; 云云羽狀包裹體羽狀包裹體; 籽籽晶晶 7、天然紅藍寶石與合成紅藍寶石的區(qū)別、天然紅藍寶石與合成紅藍寶石的區(qū)別四、

36、紅藍寶石的評價四、紅藍寶石的評價 Appraisal Color is of paramount importance when judging the value of a ruby. Prized colors-which can command high prices-are pure reds with no overtones of brown or blue. Very light or dark shades are usually less valuable, but not necessarily less appealing. Beauty is in the eye of

37、 the beholder and color preferences are subjective.Of course, clarity, cut and carat weight factor into the cost of a gem. Better quality rubies are usually eye-clean with some inclusions under magnification. Ruby is more available under two carats, gems over five carats have become scarce. In rubys

38、 finest quality, any size is rare. Appraisal of ruby紅寶石的評價紅寶石的評價顏色：顏色：最重要的因素。鮮紅或最重要的因素。鮮紅或“鴿血紅鴿血紅”淺紫紅色淺紫紅色深紫色、桃紅色、粉紅色、橙紅色等。深紫色、桃紅色、粉紅色、橙紅色等。評價紅寶石的顏色最好在上午評價紅寶石的顏色最好在上午8一一10點鐘，在自點鐘，在自然光（陽光）下進行，這是因為上午的太陽以紅然光（陽光）下進行，這是因為上午的太陽以紅色光為主，這種光線下能充分顯示紅寶石的顏色。色光為主，這種光線下能充分顯示紅寶石的顏色。 紅寶石的顏色要鮮紅而柔和，光亮度要高，紅寶石的顏色要鮮紅而柔和，

39、光亮度要高，色澤純正，濃度適中。色澤純正，濃度適中。 顏色分布要均勻。紅色均勻、鮮艷奪目的紅顏色分布要均勻。紅色均勻、鮮艷奪目的紅寶石非常稀罕也十分昂貴。大多數紅寶石都寶石非常稀罕也十分昂貴。大多數紅寶石都有顏色不均的色帶。有顏色不均的色帶。質地評價質地評價 紅寶石透明度好，少裂紋（或聚片雙晶），紅寶石透明度好，少裂紋（或聚片雙晶），可以琢磨成刻面寶石；若不透明或裂紋多，可以琢磨成刻面寶石；若不透明或裂紋多，即使顏色極佳，也只能作為素面寶石，價值即使顏色極佳，也只能作為素面寶石，價值就大打折扣了。就大打折扣了。 紅寶石透明度越好，反射光就越強，出紅寶石透明度越好，反射光就越強，出“火火”就多，

40、使寶石更加艷麗悅目，爍爍閃光。就多，使寶石更加艷麗悅目，爍爍閃光。 紅寶石晶體中若有許多包體，將嚴重影響其紅寶石晶體中若有許多包體，將嚴重影響其潔凈度，使之不能成為刻面級寶石。潔凈度，使之不能成為刻面級寶石。 切工切工 定位定位 切工類型切工類型 比例及對稱性比例及對稱性 拋光程度拋光程度 粒度粒度 自然界中紅寶石粒度大多很小，紅寶石的價值是根自然界中紅寶石粒度大多很小，紅寶石的價值是根據其重量平方向上遞增，據其重量平方向上遞增，如超過如超過5克拉的紅寶石就要克拉的紅寶石就要依其質量單獨論價了。大于依其質量單獨論價了。大于10克拉的紅寶石極為稀克拉的紅寶石極為稀罕，罕，即使在世界各地，任何一個

41、時期都不會獲得五即使在世界各地，任何一個時期都不會獲得五粒以上。粒以上。 據說緬甸政府明確規(guī)定大于據說緬甸政府明確規(guī)定大于10克拉的紅寶石視為國克拉的紅寶石視為國寶，任何私人不得擁有和出售，否則違法。由此可寶，任何私人不得擁有和出售，否則違法。由此可以看出大粒紅寶石的珍貴。以看出大粒紅寶石的珍貴。 星光紅寶石的評價星光紅寶石的評價 首先要考慮其顏色，當然以鮮紅或首先要考慮其顏色，當然以鮮紅或“鴿血紅鴿血紅”為最為最佳色佳色 其次是星光要完全，沒有斷線，并且位居寶石正中其次是星光要完全，沒有斷線，并且位居寶石正中間。星光還應清晰，使人感到星光來自寶石內部，間。星光還應清晰，使人感到星光來自寶石內

42、部，透明的星光紅寶石，十分稀罕，其價值也十分昂貴。透明的星光紅寶石，十分稀罕，其價值也十分昂貴。 一粒優(yōu)質星光紅寶石其售價可高過相同大小的優(yōu)質一粒優(yōu)質星光紅寶石其售價可高過相同大小的優(yōu)質刻面紅寶石刻面紅寶石 自然界中紅寶石完美無瑕的極少，只要顏色好，自然界中紅寶石完美無瑕的極少，只要顏色好，質地不錯，琢磨的品形好，就可認為是一粒優(yōu)質地不錯，琢磨的品形好，就可認為是一粒優(yōu)質紅寶石。質紅寶石。Dont let yourself become overly concerned about the origin of the gem. A gem from Burma may not necessar

43、ily be better than a gem from Vietnam. If the ruby has a color that appeals to you, and a clarity that looks good, then that is more important than its nationality. However, it is important to buy from a reputable dealer who will provide written documentation about the rubys size, and any treatments

44、 it has undergone. Although rubies grown in the laboratory are essentially of identical composition, hardness, and brilliance to natural rubies, they have aroused some controversy. Their presence of the market is still more limited than lab-grown emeralds, however. When buying star rubies, look for

45、a star that has straight legs that are all of equal clarityColor is of paramount importance when judging the value of sapphire. The purer the blue of a natural sapphire, the greater the price the gemstone can command. Gems that are too dark or too pale are usually less valuable, but not necessarily

46、less appealing. Beauty is in the eye of the beholder and color preferences are subjective. In recent years technology has perfected the process of heat-treating sapphires-exposing them to very high temperatures to eliminate impurities. In fact most sapphires on the market today have been heat-treate

47、d to improve clarity and color. This process is stable and does not affect the value of the gem, except at the highest level of the market. Occasionally, colorless to pale blue sapphire is diffusion treated. This process alters the color of a gem by exposing the surface to certain chemicals (the sam

48、e used by nature). The treatment is fairly stable, but it is confined to the surface of the gem only. This could create a problem, if the sapphire is ever badly chipped or nicked and needs to be recut or repolished. Diffusion treatment is not the same as heat treatment. Appraisal of SapphireAddition

49、ally, some fancy sapphire is irradiated to produce intense shades of yellow or orange. This process, however, is not very stable. The temporary color produced by this method can quickly fade in light or heat. It is important to buy fine sapphire from a reputable retailer who will provide, in writing

50、, all pertinent information regarding the gem including enhancements and special care notes. A gems clarity and cut also factor into its cost, as well as carat weight. Better quality sapphires are usually eye-clean with some inclusions under magnification. Sapphire is more available in sizes under t

51、wo carats, but gems of 5 to 10 carats are not unusual. Sapphire reaches a far greater size than ruby.The most famous source for natural gem-quality ruby is Myanmar (Burma). Good stones have also come from Thailand, Sri Lanka, and most recently, Vietnam. However, Myanmar remains the largest and best

52、source for rubies of top-quality, free of inclusions and a dark-pink red color that holds its glow in all lighting conditions. Rubies are also mined in Africa, Afghanistan, and Central Asia, but these mines have yet to yield a significant source of good rough stones. The center of the ruby trade is

53、in Thailand, in Chantaburi as well as near the Myanmar border, as close as one can get to the mines without being under the totalitarian Myanmar military government. Many of the best ruby cutting and polishing traditions are in the Thailand, and much of the international trade of finished stones tak

54、es place in Bangkok. 五、產地五、產地 Localities 緬甸北部莫谷（緬甸北部莫谷（Mogok）是世界上優(yōu)質鴿血紅是世界上優(yōu)質鴿血紅紅寶石的主要產地，曾產出過許多世界著名的紅寶石的主要產地，曾產出過許多世界著名的紅寶石，如紅寶石，如43克拉的克拉的“和平和平”紅寶石和約紅寶石和約40克克拉的拉的“切德拉帕蒂切德拉帕蒂馬尼克馬尼克”紅寶石。紅寶石。 近年來，在莫谷附近的孟素（近年來，在莫谷附近的孟素（Mong Hsu）紅紅寶石的產量巨大，經過改善的孟素紅寶石已對寶石的產量巨大，經過改善的孟素紅寶石已對世界紅寶石的市場產生了明顯的影響。世界紅寶石的市場產生了明顯的影響。 斯里蘭卡產的許多紅寶石顏色較淺，被稱為粉斯里蘭卡產的許多紅寶石顏色較淺，被稱為粉紅色藍寶石?，F收藏在美國國立博物館的紅色藍寶石?，F收藏在美國國立