Geoscience Reference
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to the slow rate of growth achieved by the earliest workers like De Senarmont and
Spezia, the captured German reports show that Nacken
[48]
, using natural
-quartz
as seed crystals and vitreous silica as the nutrient, had grown quartz crystals in an
isothermal system and had succeeded in obtaining large single crystals of quartz
from a small seed. Prof. Richard Nacken (1884
α
1971) worked on the synthesis of
various minerals from 1916 onwards, but left this field. In 1927 or 1928, he started
working only on the hydrothermal growth of quartz crystals. On Nacken's work,
Sawyer writes (cited by Bertaut and Pauthenet, 1958) that, “
Nacken made
quartz crystals of 1 in. diameter by using hydrothermal method and the conditions
are given as
...
” followed by some biographical data. Similarly, Nacken's empha-
sis on the quartz growth has also been documented by Sawyer. Almost at the same
time, Nacken made emerald single crystals by the hydrothermal method and also
beryl or corundum crystals for watch bearings. He prepared a large number of
synthetic emeralds by using a trace of chromium to produce the color and could
obtain hexagonal prisms of emerald weighing about 0.2 g in a few days
[49]
.
However, much of the work carried out by Nacken
[50]
during late 1930s and
1940s remained as intelligence reports since he could not publish much. During
1950, Nacken
[51]
published his work on quartz that remains a classic even today.
Figure 2.7
shows a photograph of the quartz crystals obtained by Nacken
[51]
.As
mentioned earlier, Doetler was the first one to use closed nickeled gun-barrel auto-
claves, way back in 1890. It attained its prominence during World War II when several
laboratories from many countries began working on the growth of large-size crystals
of quartz. This is also partly connected to the availability of alloys containing Mo and
...
Figure 2.7 Photographs of the quartz crystals obtained by Nacken
[51]
.
Source: Courtesy of the VEB Deutscher Verlag, Germany.
