History & Introduction
Agate comes from the quartz (silicon dioxide) family. Quartz mineral after feldspar
is the mineral available in plenty on the earth’s crust.
Agate was probably discovered around the 3rd or 4th century (BC) by a Greek philosopher,
Theophrastus, he named after the river 'Achates', where it was found. The Achates
River, which flows from Sicily, Italy, which is called Dirillo River now. Agate
gemstone is considered in the possession of man since ages. Jewellery during the
Stone Age, along with spear and arrow tips, is found in prehistorically grave sights.
In 3500 B.C agate were found in Egypt, even the early inhabitants of Mesopotamia,
the Sumerian styled the agate gemstone into various items like signet rings, cylinder
seals, beads, and other ornamental objects created with this versatile stone. The
agate gemstone was first discern by the Sumerians from common minerals and they
are the first to give specific gems extraordinary attributes. It was believed that
the agate gave special favour with the gods to the wearer. However, the origin of
Mesopotamia’s agate stone was never determined even though the stone was used in
plenty.
Microcrystalline aggregates the modern name used is linked to the western literature.
The Greek writer Theophrastus (372-287 B.C.) mentioned it as beautiful stones. It
is available in huge masses and in varieties of colours, hence it has different
names: cerachates [chalcedony], leucachates [chalcedony], iaspisachates [agate-jasper],
smaragdachates [green agate], haemachates [red agate or agate with red] and dendrachates
[moss agate].
There are certain colours in found in agate that purely capable of curing the sting
of deadly spiders and scorpions. As Orpheus writes that if anyone wears a piece
of the Tree-Agate upon their hand, the immortal Gods will be happy. It is explained
in Roman tradition that if a wrestler wears a specific colour of agate gemstone
than he is invincible. Pliny's writings gives methods to test a stone to be certain
as well as to see that the colour is true. Powdered agate originates from India
and is a green stone. Agate from Egypt or Crete, red in colour, is best when a cure
for spider or scorpion bites is required.
Since various ancient cultures the virtues of the Middle Eastern Lore is passed
to us. The various colours of Agate gemstone is taken with distinct and separate
virtues by the Egyptians.
Recognise - Fibrous and granular are the varieties formed when
cryptocrystalline quartz are broken. Chalcedony is the fibrous variety of quartz.
Agate gemstone is the banded type of chalcedony quartz, the specimen which is lighter
and solid-colour is called as simple ‘chalcedony’. Usually the consumers get confuse
when they go to shop agate gemstone and instead find the different kinds of it.
The reason is that the stones are in general referred to using peculiar trade names,
such as ‘banded agate’, ‘carnelian’ and ‘sardonx’, while simultaneously traded as
just chalcedony, chalcedony quartz also the plain quartz.
Availability - Agate was probably discovered around the 3rd or
4th century (BC) by a Greek philosopher, Theophrastus. He named the stone after
the river ‘Achates’ (Greek: Aχάτης), where it was found. The Achates River is situated
in Sicily, Italy, which is called Dirillo River now. Agate deposits are available
almost all over the world like Argentina, Uruguay, Australia, Myanmar, Brazil, Mexico,
Botswana, India, and the USA. Agate is usually originated alongside many other types
of rock, however it is primarily categorized as volcanic rock.
Usages - Cameos and ornamental objects are carved from Agate, and
also to famous polished slabs. It is even used in inexpensive gemstone jewellery,
mainly as beads in necklaces, earrings, bracelets and cameos. Agate is also created
to beautiful and ornate bookends and carved figures.
Buying Guide
Colour - The colours that are available in Agate gemstone are many
and in different patterns. Though, there seems to be colours that are in general
as others, almost all agate will be colourful because of unique banding. Single-colour
agates are found in original form on the earth’s crust, to get unicolor these days,
the stone is dyed. Agate with one colour are traded with names like sard and carnelian.
The colours of agate stone are red, black, white, green, blue, yellow, orange, pink,
brown, purple and grey. Agates found in South America don’t have any special markings.
They even occur naturally in a dull grey colour. Agates gemstone from the once plentiful
mines of Idar-Oberstein in Germany that at present are depleted and popular for
their vibrant and strong colours, particularly the natural pink, brown and red.
Clarity and Lustre - Naturally, cryptocrystalline quartz gets discern
from microcrystalline quartz by lustre and clarity; the cryptocrystalline clarity
ranges typically from translucent to opaque and lustre frequently maximum shows
waxy or dull like agate and chrysocolla. On the other hand, microcrystalline quartz
is even naturally shows transparent to translucent and with vitreous lustre like
citrine, amethyst and rose quartz.
Cut and Shape - Agates is also available in great sizes and with
various shapes. Number of agates are cut into en cabochon to add on their beauty,
however they are even available in free-form slabs and plain cuts. Not only this
the stone in general is used for ornamental designs such as cameos and other carvings.
Treatment - Agate is not treated naturally, however it is dyed
easily to develop the colour since it is quite porous. The price of agates are reasonable
whether they are dyed or not. In fact the sellers always disclose whatever treatments
are given to their knowledge. It is not easy to test agate for dyeing without breaking
the stone. Absence of proper equipment is found in most gem labs. Agate is the common
choice for beading and tumbled jewellery. Maximum tumbled and agate beads are dyed
to enhance colour. Bright unicolor agates, especially especially from Brazil, are
dyed naturally though untreated specimens are present.
Gemmological Characteristics: