Jewel__A_Celebration_of_Earth_s_Treasures

148 SILICATES

Banded jasper | The dramatic colour

banding in this example of jasper rough

clearly shows why it has been a popular

carving and gem material since antiquity.

Red jasper | This variety of red

jasper from Arizona, USA, shows

colour mottling that will make colourful

and interesting cabochons.

Chrysoprase | This gem chrysoprase

specimen displays a beautiful deep green

colour. Chrysoprase remains one of the most

sought-after varieties of chalcedony.

Water agate | Originating from a single locality

in Brazil, agates of this variety are actually hollow

geodes filled with preserved water, revealed by grinding

a “window” into the inside.

Heliotrope rough | This specimen consists

of heliotrope, a green variety of chalcedony

shot through with red patches of iron oxide,

for which it is also known as bloodstone.

Rough

Gem rough | This fine piece of massive gem

carnelian rough has good colour all the way

through, and excellent translucency. It is

naturally dyed with iron oxide.

Water-filled interior

Colour variations

Inclusion

Fractured edges

Colouring caused

by iron oxide

Cross-sectional

view of interior

Deep green colouring

Good

translucency

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