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BOOK V
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99
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may be large or small, sometimes striated and moderately hard. Sometimes the armatura is
the color of iron and even diamond. When it is found in an aluminous
earth it has a golden copiapite-like color and when found in other
types of earth it has the color of iron or some other material. Iron
sulphates and alum can change the iron color to that of brass which is
similar to gold. In this same locality a gray stone is found with the
same shape but entirely free of armatura. Pliny calls this tephritis. Pliny writes that hephaestites found
in Corycus has the properties of a glass in that it will reflect an
image even though it is red. The name comes from the fact that it will
set fire to dry material when held in the sun just as a concave glass
sets fire to sulphurous material, straw and small twigs. Stones of this
genus, with a dark red color, are found in the moat on the north side
of Hildesheim. They have been found the size of a dish with the red
gleam of golden armatura. This material also reflects an image
and when held in the rays of the sun will set fire to dry material.
Stones are found in this same place ornamented with armatura in such a manner that it appears to be sprinkled with gold.
Myrmecias, a black stone, derives its name from the fact that it has protuberances similar to warts. Pliny classifies it as a gemstone.27 Some stones have markings which resemble the feathers of birds, for example hieracites which Paulus Aegineta classes as a stone and is more correct than Pliny who regards it as a gem.28
This, the latter affirms, shows variable shades of black similar to
the feathers of a kite. It is found in the Hildesheim district where
the road goes from the west moat through the hills on both sides of the
river and is similar in appearance and color to the softer feathers on
the breast of hawks. Another stone is found in this same place that
resembles the feathers from the breast of a partridge, having the same
ridges and colors. Hieracites bound to the right thigh is said to stop profuse bleeding from a severed vein. Ammonites is
formed from sand in such a manner that it has the appearance of fish
roe and inside it sometimes has the same form and even the same color
and texture.
A
certain genus of stone is found in Saxony near Alfeld and Hildesheim
the size of a walnut or even larger. They belong to the same genus that
I shall describe in Book Seven. Lepidotes (mica) is similar to the scales of fish with variable colors.
I
shall describe now certain stones found in the district of Hildesheim.
A stone is found in a water course inside a cave that takes its name
from dwarfs, with a dark color, tabular form, as harsh as sal ammoniac
and having protuberances on the upper surface that resemble the heads
of nails. Another stone is found near Hasda which is similar except
that it is white and has no protuberances. In the mountainous region
where the tem-
27
Pliny, Book 37, Chapter 72, describes this mineral as amber, or a
mineral containing an ant. He makes no mention of protuberances. The
name is derived from the word for ant, myrmeois.
28 Probably arborescent coatings on rocks.
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