Categories
Education
In this, the final instalment, we learn what factors are involved when determining the value of an Opal and the meanings behind some of those terms used throughout my 7 part series.
Valuing Opals
When determining the value of an opal, several factors are involved:
Type of opal
Soundness
Base colour
Fire colour
Colour pattern
Brightness of fire
Background (base) Colour:
Solid precious opal is more valuable than a doublet or triplet, and black opal is more valuable than boulder opal, and so forth. The darker the body colour, the more valuable the gem.
Fire Colour:
The clarity of the opals colour is critical when determining the value of the opal. Opal is graded according to its colour, with red fire being the most rare, followed by green/orange, green/blue, blue, and finally, purple. However, brilliance and clarity of colour, along with proportional pattern are the main decision makers; a brilliant blue/green opal can cost more than a dull red. An opal displaying a bright “pinfire” pattern can cost more than a cloudy open pattern of similar colouration.
Colour Pattern:
Nearly all opal displays some type of pattern, with no two opals being alike.
The various patterns are:
Harlequin:
The most prized of all nice patterns and its name is derived from its likeness to floral dress material.
Pinfire:
Closely resembles a mass of pinheads in different colours.
Mobile rolling Flash:
Consists of one colour, which travels across part of or all of the stone as it is moved.
Palette Pattern:
As the name suggests, resembles an artist’s palette.
Soundness:
Opal should be free from cracks and flaws.
OPAL DICTIONARY
TERM
Agitator: Modified cement mixer used to wash dirt away
from precious opal.
Boulder Opal: Formed in cavities and cracks of Ironstone,
usually from Queensland, Australia.
Black Opal: Naturally occurring solid opal with a coloured
face and black backing.
Blower: A large truck mounted vacuum cleaner used to
suck dirt to the surface.
Cabochon: The rounded surface of a cut stone.
Crystal: Transparent/translucent opal.
Doublet: Opal with an attached dark coloured backing.
Drive: A horizontal underground tunnel.
Free-Form: A naturally shaped opal – something other than
oval or round stone.
Harlequin: Type of opal pattern with a checkerboard
appearance, rare and expensive.
Hoist: A bucket attached to a framework in a shaft,
used to carry dirt to the surface.
Level: Usually the layer of opal bearing dirt.
Matrix: Any material with specks running through it.
Nobby: Nodule of opal almost exclusively from
Lightning Ridge.
Parcel: A collection of any number of opals, either
rough, rubs or cut, offered for sale.
Pinfire: Type of opal pattern where specks of different
colour covers the whole stone.
Potch: Opal without any colour, also called common
opal.
Puddler: Forerunner of the agitator, a mesh drum.
Rough: Opal in its natural state, as it comes out of the
ground.
Rubs: Opal pieces intially shaped with the waste material,
sand removed but not yet cut and polished.
Seam: Opal found in a layer rather than in nobbies.
Shaft: A vertical hole down to a mine.
Solid: A natural occurring solid piece of opal, cut into a
stone.
Tailings: Material left after opal dirt from the mine has
been washed.
Triplet: A stone comprising a thin layer of natural opal
with an attached dark backing and a clear quartz
capping.
Windlass: Forerunner of the hoist, hand operated device for
raising buckets of opal dirt to the surface by
by means of a cable and drum with handles.
Yowah Nut: Small ironstone boulder, containing opal either as
a solid kernel or in concentric layers.
That concludes this 7 part series. I hope you have enjoyed reading - "Natures Fireworks" - A begginers Guide to Opal.
Together, these six articles when printed out, combine to give the novice, opal enthusiast or collector who has a little or no understanding of opals an insight into the world of these Queen of Gems.
Best wishes and have a great day
Stuart Bazga
www.kulpunyaopals.com
Kulpunya Opals was established several years ago to provide the UK and Europe with a specialist supply of opals. We import directly from key suppliers in Australia with whom we have developed strong and long-term relationships. This ensures the products are always of the highest quality, and each represent excellent value.
Article Source: http://www.LinkSnoop.com
Articles
