Grading System

OFM Cheatsheet

Origin (Metafield)
-----------------
Northern Territory
Queensland
New South Wales
South Australia

Lightning Ridge
Andamooka
Coober Pedy
Lambina
Mintabie
Opalton
Quilpie
White Cliffs
Winton
Yowah

Grade (Vendor)
--------------
Top Gem Grade
High Grade (Cutters)
Good Quality
Gamble Grade
Low Grade

Type
----
Boulder Fairy
Boulder Matrix
Boulder Opal
Knobby Opal
Matrix Opal
Opal Chips
Opalised Fossils, Woods and Shells
Seam Opal

State (Tags)
------------
Rough
Rubbed
Finished

Pattern (Metafield)
-------------------
Broadflash
Flagstone
Floral
Harlequin
Mackerel Stripe
Peacock
Pinfire
Straw Pattern

Shape (Metafield)
-----------------
Cushion
Freeform
Oval
Rectangular
Round
Square
Tear Drop
Marquis
Heart
Triangle
Baroque
Non-standard