Nature's Fireworks - A Beginner's Guide to OPAL Parts 6 /7: Valuing Opals and Opal Dictionary

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