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About Mystic Topaz- History and Introduction

Color

Color Description; Occurrence

1 ct.

3 ct.

5 ct.

10 ct.

30 ct.

045 - light Yellow; very slightly brownish

Alternative name, occurrence category: Common

13,38

13.70

14.03

14.84

18.10

021 - light reddish Orange; very slightly brownish

Alternative name, occurrence category: Common

22.02

22.55

23.09

24.43

29.79

024 - medium light reddish Orange; slightly brownish

Alternative name, occurrence category: Common

22.84

23.40

23.96

25.35

30.91

048 - medium light Yellow; slightly brownish

Alternative name, occurrence category: Common

25.92

26.55

27.18

28.76

35.07

033 - medium light Orange; very slightly brownish

Alternative name, occurrence category: Common

72.50

74.26

76.03

80.44

98.09

022 - medium light reddish Orange; strong

Alternative name, occurrence category: Rare

119.49

122.40

125.31

132.58

161.67

025 - medium reddish Orange; strong

Alternative name, occurrence category: Rare

143.28

146.77

150.26

158.98

193.85

017 - medium orangey Red; very slightly brownish

Alternative name, occurrence category: Rare

136.53

139.86

143.18

151.49

184.73

034 - medium Orange; strong

Alternative name, occurrence category: Rare

115.64

118.46

121.27

128.31

156.46

038 - medium light orangey Yellow; strong

Alternative name, occurrence category: Rare

84.16

86.21

88.25

93.38

113.86

187 - very light Purple

Alternative name, occurrence category: Rare

202.23

207.15

212.07

224.38

273.61

199 - light reddish Purple; strong

Alternative name, occurrence category: Rare

253.07

259.23

265.39

280.79

342.39

114 / 021 - bi color: medium light very strongly bluish Green; very slightly greyish / light reddish Orange; very slightly brownish

Alternative name, occurrence category: Rare

66.05

67.66

69.26

73.28

89.36

127 - very light very strongly greenish Blue; Untreated

Alternative name, occurrence category: Common

22.61

23.16

23.71

25.08

30.59

134 - medium very strongly greenish Blue; very slightly greyish. Irradiated.

Alternative name, occurrence category: Common

15.03

15.40

15.76

16.68

20.34

140 - medium light very slightly greenish Blue; strong. Irradiated.

Alternative name, occurrence category: Common

11.36

11.64

11.92

12.61

15.37

130 - medium light very strongly greenish Blue; strong. Irradiated.

Alternative name, occurrence category: Common

7.99

8.18

8.38

8.86

10.81

113 - medium light very strongly bluish Green; very slightly greyish. Irradiated.

Alternative name, occurrence category: Common

6.51

6.67

6.83

7.22

8.81

105 - medium light bluish Green; very slightly greyish. Irradiated.

Alternative name, occurrence category: Common

6.39

6.55

6.70

7.09

8.65

209 - medium light strongly purplish Red; very slightly brownish. Diffusion / coating treatment.

Alternative name, occurrence category: Common

5.74

5.88

6.02

6.37

7.77

191 - medium light Purple; very slightly greyish. Diffusion / coating treatment.

Alternative name, occurrence category: Common

6.16

6.30

6.45

6.83

8.33

095 / 201 - "mystic topaz" surface treatment, kaleidoscope colors. Coating treatment.

Alternative name, occurrence category: Common

6.45

6.61

6.76

7.16

8.73

022 / 218 - "azotic topaz" surface treatment, kaleidoscope colors. Coating treatment.

Alternative name, occurrence category: Common

6.27

6.43

6.58

6.96

8.49

223 - colorless

Alternative name, occurrence category: Common

5.50

5.64

5.77

6.11

7.45

About Topaz - History and Introduction

Topaz is an aluminium silicate that contains fluorine and hydroxyl. In its pure form it is colourless (white). Impurities are what cause variations in colour. Topaz has a history that goes back at least two thousand years. The use of topaz goes back to Egyptian times when the ancient Egyptians believed that yellow topaz received its golden hue from the Sun God, Ra. Some believe that "topaz" is a Middle English word, which was acquired from the Old French word "Topace" and Latin "Topazus", the root of which is in the Greek word "Topazios" or "Topazion"; the ancient name of an island in The Red Sea where the ancient Greeks mined a yellow gem that they believed to be topaz. The name of the island means "to seek" in Greek. It could have been so named because it was difficult to find amongst the mist. This island is now known as "Zabargad" or "St John's Island", and it is thought that the gem mined by the ancient Greeks was actually "chrysolite". The Christian Old Testament makes references to topaz, but this gemstone may have also been "chrysolite", rather than topaz. The word "topaz" could also have stemmed from the Sanskrit (the ancient language of India) word, "tapas", which means "fire".

Topaz can be distinguished from diamond, ruby, sapphire, citrine, apatite, brazilianite, zircon, fluorite, kunzite, tourmaline and orthoclase by its hardness (8 on the Mohs scale). It can be told apart from aquamarine by its orthorhombic crystal structure. Phenakite can be distinguished from topaz by its trigonal crystal structure. Spinel can be identified from topaz by its cubic crystal structure. Topaz has a lower density and different chemical composition than chrysoberyl, and chrysoberyl usually has no fluorescence, whereas topaz has some weak fluorescence, which can help to distinguish between the two. Precious beryl can be mistaken for topaz, but has indistinct cleavage, whereas topaz displays perfect cleavage. A lot of other less valuable gems are misleadingly sold as "topaz", such as Madeira topaz, occidental topaz, Palmeira topaz, Rio topaz, saffranite topaz, Scottish topaz, smoky topaz and Spanish topaz. However, in most cases, these gems are citrine quartz, with the exception of smoky topaz, which is smoky quartz. Indian topaz, king topaz and star topaz are all actually sapphire. Diamond has a Mohs scale hardness score of 10, so it differs from white topaz in this respect. Topaz is softer than ruby and sapphire, which both have a hardness of 9 on the Mohs scale. Topaz also exhibits pleochroism, which is the appearance of several colours in a single stone depending on the viewing angle. Most other similar gemstones do not typically exhibit pleochroism.

Topaz; Origin and Gemstone Sources Back to Top

Deposits of topaz have been found in Brazil, Afghanistan, Australia, Myanmar (Burma), China, Germany, Japan, Madagascar, Mexico, Namibia, Nigeria, Pakistan, Russia, Zimbabwe, Sri Lanka, Ukraine and the USA. Natural light-blue topaz is found in Northern Ireland and the UK. Enormous topaz crystals have been discovered in Minas Gerais (Brazil) and Ukraine.


Buying Topaz and Determining Topaz Gemstone Value Back to Top

Topaz Colour

Topaz ranges from colourless (white) to yellow, orange, red-brown, light to dark-blue, pink to red, violet and light-green. This is the reason why it can be mistaken for many other gemstones. Naturally coloured topaz gets its colour from iron and chromium; the impurities cause colour, whereas pure topaz is colourless. Most unadulterated topaz is colourless or pale blue. The most rare and valuable topaz is yellow, or pink to reddish-orange, and is known as "imperial topaz" or "precious topaz". Some yellowish-brown topaz gems can gradually fade when continually exposed to daylight. Red and violet topaz is incredibly rare. A lot of topaz is treated in order to enhance the colour. Reputable gem sellers declare any enhancements.

Topaz Clarity and Lustre

Topaz is transparent to translucent. It exhibits high clarity with few inclusions, so topaz gemstones can be examined by the naked eye and found to be "eye clean", which means that no imperfections can be seen. Topaz is highly prized for its brilliance and vitreous (glassy) lustre.

Topaz Cut and Shape

Topaz is a very versatile material. Therefore it can be cut into a great variety of shapes, such as square, round, octagon, pear, oval, heart and even fancy shapes such as fish or birds. Strongly coloured gemstones are usually scissor cut whereas weakly coloured stones are generally brilliantly cut. The facets show off the clarity and brilliance of the gem. When topaz has irregular inclusions, it is often cabochon cut. Its hardness makes it resistant to scratches. However, lapidarists must handle topaz carefully, due to its perfect cleavage, which means that it can easily fracture.

Topaz Treatment

Topaz is often enhanced to produce the most desirable colours. The most popular colour for topaz is blue, but in nature, blue topaz is usually pale blue rather than bright or deep blue. The brilliant blue shades of topaz are usually achieved by artificial means. Topaz is exposed to radiation (a process known as irradiation) and then usually heated, to produce striking blue colours. A deep blue enhanced topaz is known as "London blue"; medium blue is called "Swiss blue" and light-blue is termed "sky blue". This blue colour treatment is usually performed on greyish-blue or silver-grey gemstones. The darker blue shades are more valuable because more energy is needed to produce darker colours. Orange-brown topaz is heat-treated during a process known as "pinking", which produces a purplish-pink colour. These processes are widely accepted, since they result in permanent colour change, however, they should be declared by traders. There are strict rules regarding the handling of irradiated gemstones, to ensure the safety of gem handlers and buyers. Naturally pink topaz is rare and is usually a pale shade of pink. It occurs in Pakistan.

A thin coating of titanium dioxide vapour can be applied to topaz stones. Topaz can also be coated to change its colour. Coatings are not permanent and can gradually fade over time. Stones that have been treated in this way should not be re-cut, since the coating will be taken off and reveal a different, undesirable colour inside. Coating treatment produces iridescent stones known as "mystic topaz". Azotic topaz is white topaz that has been colour-enhanced by coating it with a thin film which gives it rainbow colours. It is named after the company that patented the Azotic process. Topaz is also coated to produce vivid pink and imitation "imperial topaz". White topaz can also be exposed to diffusion treatment, which means that it is exposed to chemicals and heat, to change the surface colour. This treatment is performed to produce "green topaz", but the treatment only changes the surface colour, so that if the gem is re-cut, the original, undesirable colour will be revealed. As with irradiation, any surface treatments or coatings are declared by reputable gem sellers. Natural topaz can also be found

TOP

Historical values 2005 - 2016

Topaz

Colour: blue, yellow, pink, red, brown, green, colourless

Hardness: 8

Refractive index: 1.60 - 1.64

Density: 3.50 - 3.58

Chemical composition: Al2[SiO4](F,OH)2

Crystal structure: orthorhombic

Origins: Brazil, Madagascar, Russia, USA, Mexico, Pakistan.

The most valued colour for a topaz is orangey-pink (an example being the imperial topaz from Brazil). Heat treatment is common for yellowish stones, with light blue or colourless stones being subjected to x-ray treatment and heating. Very big, clean crystals are common. Topaz prices subject to noticeable variation due to fashion trends on local markets.