134 SYSTEMATIC DESCRIPTION OF PRECIOUS STONES 



background of pure white, will fail to recognise that the stone is coloured at all. The 

 practised eye of the diamond merchant, however, needs no such assistance in recognising the 

 most faintly coloured stones. Such stones are rather lower in value than absolutely 

 colourless specimens of the same clearness and transparency, but the difference in 

 price is not very considerable. The shades of colour which appear most frequently 

 ai-e light yellow, grey, and green. A faintly yellow diamond is not observable as 

 such in any artificial illumination other than the electric light, and then appears 

 to be a colourless stone. Diamonds of a faint bluish tinge are known, but are much 

 less common. 



As mentioned above, diamonds showing a pronounced colouration constitute about 

 one-half of the total output. Almost all the colours of the mineral kingdom may be 

 represented in numerous and varied tints, so that the suite of colours of the diamond 

 is very extensive. A magnificent collection of differently coloured diamonds, the most 

 beautiful and the richest in existence, is preserved in the treasury of the royal palace at Vienna. 

 It was brought together by Helmreichen, who spent many years in Brazil, and was so enabled 

 to make the series very complete. The colour which occurs most frequently in diamonds is 

 yellow, in various shades, such as citron-yellow, wine-yellow, brass-yellow, ochre-yellow, and 

 honey-yellow, but sulphur-yellow has not as yet been observed. Most of the Cape diamonds 

 are coloured with one or other of these tints of yellow. After yellow, gre in is the most 

 commonly occurring colour, especially in Brazilian diamonds. Oil-green or yellowish-green 

 is seen most frequently, then pale green, leek-green, asparagus-green, pistachio-green, olive- 

 green, siskin-green, emerald-green, bluish-green and greyish-green. Brown diamonds are 

 also common at all localities ; the different shades are light-brown, coffee-brown, clove- 

 brown, and reddish-brown. Shades of grey, such as pale grey, ash-grey, smoke-grey, are not 

 rare. Black diamonds in well-formed crystals are unusual. The different shades of red, a 

 colour which is rarely met with in diamonds, are lilac-red, rose-red, peach-blossom-red, 

 cherry-red, hyacinth-red. Blue in its two shades, dark blue and pale sapphire-blue, is the 

 rarest of all colours to be met with in diamonds. 



The colouring of diamonds is seldom intense, pale colours being much more usual than 

 deeper shades. Diamonds which combine great depth and beauty of colour, with perfect 

 transparency, are objects of unsurpassable beauty ; for, in addition to their fine colour, they 

 possess the wonderful lustre and brilliant play of prismatic colours peculiar to the diamond, 

 so that other finely-coloured stones, such as ruby and sapphire, are not to be compared with 

 them. Only a few stones of this description are in existence ; they are among the most 

 highly-prized of costly gems. 



Of such deeply coloured and perfectly transparent diamonds, bright or deep yellow 

 specimens are, since the discovery of the South African diamond-fields, the least rarely met 

 with. The largest of these yellow Cape diamonds is shown in Fig. 52 ; it is a beautiful 

 orange-yellow brilliant, weighing 125f carats, and is in the possession of Tiffany and Co., the 

 New York firm of jewellers. A few fine yellow stones dating back to ancient times are 

 preserved in the " Green Vaults " at Dresden. 



Diamonds of a fine green colour are distinctly rare, only a few examples being known; 

 the same may be said of red diamonds and, even more emphatically, of blue diamonds. The 

 most beautiful green diamond known is a transparent brilliant weighing 4<8| carats, preserved 

 in the " Green Vaults " at Dresden ; it will be again mentioned in the section devoted to 

 famous diamonds. Another green diamond of the same quality is now in America. Tschudi 

 mentions two beautiful specimens from Brazil, one of an emerald-green and the other of 

 a sea-green colour, while the existence of other Brazilian stones with a colour very similar to 



