ganese oxide adorn a milky white agate, in a way suggestive of a
sub-aquatic scene in a coral reef. This thin, polished slice measures 16 x 30 mm. and is photographed with transient light.
SU
A E This fine detail of a polished 'moss-agate', not
much larger than a thumbnail, looks like sea-grass, gently moving with the heaving of the waves. But actually these are dendritic crystals of manganese oxide, not really organic at all.
Here again, one feels that the separation between these two
domains, the organic and the inorganic, does not have to be
taken as absolute as is always implied.
Agate is a hybrid term, widely used in the world of semi precious stones. The name goes back to Roman times and is first
mentioned by Pliny the Elder, who refers to a then existing
river Achate in Sicily, in which this type of stone was found. In a
broader sense agate designates a type of stone, composed of
'chalcedony' (SiD,), which is deposited, from aqueous solutions, inside a vein or hollow space in a rock, as described in
the previous chapter.
Agates are known in many places around the world, most commonly in regions of volcanic rock. Very hard and resistant to
weathering, pebbles of agate can be found far from their place
of origin, in downstream river deposits or on pebbly beaches.
The circumstances under which agates grow can vary from one
place to the other, leading to great diversity in form, banding
and color. Associated minerals, like manganese or iron oxide,
often crystallize in 'dendritic' (branch-shaped) or rosetteshaped patterns inside the chalcedony. Veteran collectors can
recognize the region, sometimes even the exact place of origin
of an agate. Agate has been used for decoration and as a semi
precious stone by many cultures for thousands of years. Large
pieces may be worked into such objects as bowls or vases,
smaller ones into animal figures or other trinkets. Very fine
qualities are used for jewelry. Most striking are cameos and
intaglios, those delicate gems for brooches or necklaces that
are carved in such a manner that differently colored layers in
the agate accentuate the renderings. The plates in this chapter
show polished surfaces in reflected light, as well as translucent
slices photographed in transmitted light. The fantastic images
that materialize in agates defy the imagination.
ESC
Delicate dendrites and rosettes of a manAGA E
translucent chalcedony bend upwards in the same way that
huge strata curve up on the slope of a volcano. The title of this
exposure was inspired by Malcolm Lowry's superb novel, in
which such an ominous suspense burns under the surface of
the narrative. Actual size 50 x 70 mm.
SU
The intricate finesses of dendritic minerai growth, in this landscape agate, are a challenge to anybody's
imagination. Actual size 13 x 22 mm.
B 0<. A garland of white chalcedony decorously girdles
the periphery of this slice of agate that comes from the
renowned area around Idar-Dberstein. referred to in the introduction of the previous chapter. Actual size 45 x 60 mm.
RGATO Y Through fire and torments the heavenly portal
beckons'. Somehow a notion of the purgatory radiates from
this thin slice of agate. Actual size 50 x 70 mm.
L1TT
SHI ROCK Shiprock is a conspicuous, pointed
mountain of dark basalt, protruding 500 meters out of the
desert plane in New Mexico, USA (see page 19).The precipitation of manganese-oxide, in this nail-sized landscape agate, has
an allusive resemblance to the real Shiprock, including the
crested dykes that fan out from the central mount into the
desert.
TO
SPUMOSO This and several other pictures in
this chapter are made of agates from a location called
Espumoso, in Brazil. These sophisticated 'landscape agates',
speckled with refined deposits of manganese- and iron-oxide,
are much sought after by collectors. They are cut and polished
into thin little slices, an art mastered by the best professionals
of the trade only. Actual size 18 x 25 mm.
1M RIESE
Morgen im Riesengebirge is an allegorical painting by Caspar David Friedrich, depicting a crucifix
planted on a ridge of jagged rocks in the Riesengebirge of eastern Germany. This image was created millions of years earlier,
by the whims of nature, in a small slice of Brazilian landscape
agate. It might well have astounded the artist. Actual size 20 x
25 mm.
UNDER THE VOLCAN Thin bands of iron oxide inside
80
BOTSWANA AGArE Botswana agates are very special,
sub-aquatic scene in a coral reef. This thin, polished slice measures 16 x 30 mm. and is photographed with transient light.
SU
A E This fine detail of a polished 'moss-agate', not
much larger than a thumbnail, looks like sea-grass, gently moving with the heaving of the waves. But actually these are dendritic crystals of manganese oxide, not really organic at all.
Here again, one feels that the separation between these two
domains, the organic and the inorganic, does not have to be
taken as absolute as is always implied.
Agate is a hybrid term, widely used in the world of semi precious stones. The name goes back to Roman times and is first
mentioned by Pliny the Elder, who refers to a then existing
river Achate in Sicily, in which this type of stone was found. In a
broader sense agate designates a type of stone, composed of
'chalcedony' (SiD,), which is deposited, from aqueous solutions, inside a vein or hollow space in a rock, as described in
the previous chapter.
Agates are known in many places around the world, most commonly in regions of volcanic rock. Very hard and resistant to
weathering, pebbles of agate can be found far from their place
of origin, in downstream river deposits or on pebbly beaches.
The circumstances under which agates grow can vary from one
place to the other, leading to great diversity in form, banding
and color. Associated minerals, like manganese or iron oxide,
often crystallize in 'dendritic' (branch-shaped) or rosetteshaped patterns inside the chalcedony. Veteran collectors can
recognize the region, sometimes even the exact place of origin
of an agate. Agate has been used for decoration and as a semi
precious stone by many cultures for thousands of years. Large
pieces may be worked into such objects as bowls or vases,
smaller ones into animal figures or other trinkets. Very fine
qualities are used for jewelry. Most striking are cameos and
intaglios, those delicate gems for brooches or necklaces that
are carved in such a manner that differently colored layers in
the agate accentuate the renderings. The plates in this chapter
show polished surfaces in reflected light, as well as translucent
slices photographed in transmitted light. The fantastic images
that materialize in agates defy the imagination.
ESC
Delicate dendrites and rosettes of a manAGA E
translucent chalcedony bend upwards in the same way that
huge strata curve up on the slope of a volcano. The title of this
exposure was inspired by Malcolm Lowry's superb novel, in
which such an ominous suspense burns under the surface of
the narrative. Actual size 50 x 70 mm.
SU
The intricate finesses of dendritic minerai growth, in this landscape agate, are a challenge to anybody's
imagination. Actual size 13 x 22 mm.
B 0<. A garland of white chalcedony decorously girdles
the periphery of this slice of agate that comes from the
renowned area around Idar-Dberstein. referred to in the introduction of the previous chapter. Actual size 45 x 60 mm.
RGATO Y Through fire and torments the heavenly portal
beckons'. Somehow a notion of the purgatory radiates from
this thin slice of agate. Actual size 50 x 70 mm.
L1TT
SHI ROCK Shiprock is a conspicuous, pointed
mountain of dark basalt, protruding 500 meters out of the
desert plane in New Mexico, USA (see page 19).The precipitation of manganese-oxide, in this nail-sized landscape agate, has
an allusive resemblance to the real Shiprock, including the
crested dykes that fan out from the central mount into the
desert.
TO
SPUMOSO This and several other pictures in
this chapter are made of agates from a location called
Espumoso, in Brazil. These sophisticated 'landscape agates',
speckled with refined deposits of manganese- and iron-oxide,
are much sought after by collectors. They are cut and polished
into thin little slices, an art mastered by the best professionals
of the trade only. Actual size 18 x 25 mm.
1M RIESE
Morgen im Riesengebirge is an allegorical painting by Caspar David Friedrich, depicting a crucifix
planted on a ridge of jagged rocks in the Riesengebirge of eastern Germany. This image was created millions of years earlier,
by the whims of nature, in a small slice of Brazilian landscape
agate. It might well have astounded the artist. Actual size 20 x
25 mm.
UNDER THE VOLCAN Thin bands of iron oxide inside
80
BOTSWANA AGArE Botswana agates are very special,