Brooch the subject of semi-precious stones.
AGATES are one of the most attractive of all semi-precious stones, popular both for jewellery and as specimens to collect in their own right.
Geologically speaking, agates are nodular masses comprising one or more varieties of quartz, particularly chalcedony. They usually form inside gas cavities in the volcanic rocks andesite and basalt.
Part of the fascination of agates is the wide range of forms and colours they can exhibit, no two agates looking exactly alike.
Shown here are two common varieties of agate: banded, and moss or dendritic agate. Banded agates are formed by the successive deposit in layers of siliceous material, while moss and dendritic agates consist of branching inclusions of mainly manganese inside chalcedony, dendritic agates being like the pendant pictured that resemble ferns or trees.
Agates have been prized since ancient times and were actually named by the Ancient Greeks after the river Achates where they were first found. Both the Greeks and the Romans used them for hardstone carvings and later on an important centre for agate polishing and carving was established at Idar-Oberstein in Germany.
At first, from the 1400s onwards, the cutters in Idar-Oberstein used locally-sourced material found along the Nahe river but when supplies ran out in the 19th century they started importing agates from Brazil and elsewhere.
Agates are also found in Britain and hunting for them can be an enjoyable pursuit. I've picked up many agate pebbles myself from beaches in Norfolk and north-east Scotland, Scotland in particular being famous for its agates.
Unfortunately, we're not blessed with many decent agate localities in Wales. They can occasionally be found in some coastal sites near Aberystwyth, in South Pembrokeshire and to the north of the Lleyn Peninsula, but are not of great quality.
Collectors of agates particularly look for the fine specimens that present beautiful vistas when cut open and polished.
Agates are often named after the sort of image the banding seems to delineate, such as flame, eye, landscape and fortification agates.
Agates can make attractive brooches and pendants, although their beauty is best appreciated when held up to the light rather than worn.
Sliced thinly, as they often are for jewellery, agates can be quite fragile so you need to check for cracks, as damage considerably devalues a piece. These brooches and the pendant were all picked up for pounds 10 or less but you would normally expect to pay two or three times this for them.
Examples of agate brooches
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|Publication:||Western Mail (Cardiff, Wales)|
|Date:||Aug 21, 2010|
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