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Book VI gems: diamond, emeralds, sapphire, topaz, chrysoberyl, carbuncle, jaspis
Page
of 251
Text size:
138
DE NATURA FOSSILIUM
of stars set in almost the same position as the stars of the Hyades,
41
according to Pliny, it was used in Chaldean ceremonies. These points are not as conspicuous when the gem is examined in the sunlight as when it is set in a ring. The more brilliant gems are called masculine, the less brilliant, feminine. Like the
carchedonius
species of
carbunculus
this gem is not injured in a fire.
42
The
chrysolithus
which the gem dealers today call
hyacinthus
differs from
sandasiros
in the number of golden points it contains. The latter has only a few, the former a large number. It is found in Spain, Pontus, Bac-tria, India, Arabia and Ethiopia. The color of the stone may be golden yellow, hence the name, reddish yellow or similar in color to the
carchedonius carbunculus
which they call
granatus
but with a golden luster. Some of the stones have a color similar to amber and are called
chryselec-tros.
When the finest stones are placed next to gold they become whitened and have a silvery appearance. The less valuable and worthless stones have a variable color due to white and black spots. The stones that appear to have smoke through them are called
capniae
by the Greeks; those with a honey-yellow color,
melichrysos
because, according to Pliny, they have the appearance of gold shining through clear honey.
43
When a stone has a white band through it they called it
leucochrysos.
The stones that are full of scales, hairs or are not clear have a luster similar to saffron-yellow glass. Only the transparent stones are placed in open settings while those containing a cloud of spots that spoil the brilliancy are set in rings. Formerly gem setters were in the habit of placing brass foil on the back of these stones but now they use foil with a color which almost matches that of the stone. Pliny writes that the first quality stones come from India, the second quality from Bactria if they are not variegated while those from Arabia are the poorest. Some are hard, some soft. The
melichrysos
from India is very fragile. The Pontician stones are very light. Bocchus writes that he had seen Spanish stones weighing twelve pounds. I myself have seen masses taken from our own mines that weighed more than sixty pounds. These stones have a rectangular shape, especially those stones about one inch wide and two inches long. They are all so soft that they cannot be polished.
44
Craterites
is very hard with a color between
chrysolithus
and amber.
45
41
A group of seven stars in the constellation Taurus.
42
There is obvious confusion in this description. The reddish yellow color, dark smoky appearance and infusibility indicate that it is garnet or sapphire with solid mineral inclusions or aventurine quartz. The "infusible garnets" mentioned by Agric-ola and older writers were probably our corundum.
43
This is an excellent description of a stone backed with foil.
44
From this description one could identify a number of minerals with
chrysolithus,
topaz, barite, smithsonite, etc. Undoubtedly many of the descriptions by older writers referred primarily to the topaz. Agricola undoubtedly saw crystals of topaz but since this mineral ia uncommonly hard one can only speculate as to the identity of the soft mineral. It may have been barite, fluorite, etc.
44
Probably the golden yellow sapphire.
Page
of 251
Table Of Contents
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Agricola. Textbook of Mineralogy.
Front page, forword and index
To the illustrious duke of saxony and thuringia and misena prince of Maurice
Book I Minerals color, taste, odor , physical properties of gemstones and minerals such as emeralds, diamonds, rubies, sapphires
Book II About different applications of earths (painting, medical) and their occurrences
Book III about halite and nitrium, alum and acrid juices and related minerals, sulphur, bitumen, realgar, and orpiment; the fourth, chrysocolla, aerugo, caeruleum, ferrugo
Book IV Sulphur, amber, Pliny's gems, jet, bitumen, naphtha, camphor, maltha, Samothracian gem, thracius stone, obsidianus stone
Book V about lodestone, hematite, geodes, hematite, selenite, lapis secularum, asbestos, mica
Book VI gems: diamond, emeralds, sapphire, topaz, chrysoberyl, carbuncle, jaspis
Book VII marbles, gems in rings and other applications
Book VIII metals, precious such as gold, platinum, silver
Book IX artificially coloring of metals such as gold, silver, copper
Book X lapis sabinicus, lapis selentinus, lapis liparaeus and other mixtures of stone, metal and earth
Latin Mineral Index
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