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yellow
brilliant of 128-1/2 carats and belongs to Tiffany & Co. of New
York. It was found in the Kimberley mine at Kimberley, South Africa.
Chapter XII
THE CORUNDUM FAMILY—RUBY AND SAPPHIRE
Introduction
Ruby,
sapphire and emery were known to the ancients, but their true
relationship came to be realized only recently. Formerly the spinels
were also classed with the rubies, but are now separated. Charles
Francis Greville in 1798 introduced the now well-known name 'Corundum'
for this mineral species. Count de Bournon was also responsible for
classifying corundum (1802), but the eastern nations had known it for
several centuries. The origin of most corundum, ruby and sapphire in
ancient times was from the east. The name is also of Indian origin,
'korund' in Hindi and 'kuruvinda' in Sanskrit. The ruby is known as
'oriental ruby' or 'Padmaraga' (= red lotus) which was the best
favourite and most valuable of all gem-stones. The ancient writers
described it as'having the power of shining in the absence of all
light, the fact being the ruby becomes phosphorescent by being exposed
to the sun. Ruby is spoken of in the book of Job, in the Proverbs and
the Bible. The breast plate of the high priest is said to have had
rubies set in it.
Physical Characters
Ruby
is the gem variety of corundum, which crystallizes in therhombohedral
form. Corundum and ruby crystallize in flat forms with the basal
pinacoid and rhombohedron, and the sapphire in double pyramids with the
basal pinacoid. The angle between the normals to the basal pinacoid
and rhombohedron is 57° 34' which is a fundamental
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