• • Abanderada; a mexican term describing the patter formed from the sedimentary or banded build-up of colour horizons, which gives a banded or flag-stripe effect. This pattern notably occurs in Queensland boulder opal.
• Azules; a jelly-type opal with a haze of blue-mauve irisisations.
• Blue; a variety of opal in which brilliant blue, indigo, and violet are prominent. This description can be used in combination with others, e.g. 'blue flash black opal'.
• Broken Flash; similar to flash, but with two or more areas of colour, each visible from a different angle.
• Chaff; intermixed and indefinitely rounded colour units, exhibiting very distinguishable, aligned packing-fault lineations in each unit.
• Chinese Writing; fanciful description of either potch or opal slashed with differently patterned noble opal, giving a similarity to chinese caligraphy.
• Contra Luz; opal showing colour play when viewed against the light.
• Exploding Flash; a flash pattern which appears to explode outwards in all directions as the stone is moved.
• Eye-of-Opal; an eye-like effect when opal infills a cavity.
• Fiery; any opal which has a dominant red hue. The term 'red' is also sometimes used in this case.
• Flame; colours are arranged in a quite regular streaked effect, giving appearance similar to that of crackling flames.
• Flash of Fire; another term for flame.
• Flash; a striking pattern showing a single pronounced flash of colour right across the whole surface of the cut stone. The colour will change as the stone is turned, and at certain angles will extinguish completely. This pattern shows that the stone lacks trueness.
• Golden; showing predominantly orange/yellow colour play, or with a golden base tone.
• Gossamer Veil; when the colour play is not in distinctive colour units, but appears as a 'flimsy gauze' of delicate irisations.
• Grass; colour units showing packing-fault lineation, giving the appearance of blades of grass.
• Green; any opal with predominantly green colour play.
• Harlequin; see Harlequin.
• Iris Pattern; Irisation which appears as a colour sheen in opal.
• Lechosos; a mexican term describing a milky-white opal with green irisations.
• Liquid; a rare pattern of remarkable mobility which always appears to move in the same direction regardless of the way the stone is turned.
• Mackerel Sky; all colours may be present, in bands arranged liike clouds broken into long, thin, parallel masses.
• Moss; dissipated green effect with the appearance of moss.
• Night Stone; an opal of such high quality that its colour is visible even in dim light.
• Pinfire; very small or pinpoint sized specks of colour. The most outstanding examples are those in which these specks display only one colour, which changes as the stone is turned.
• Peacock's Tail Pinfire; a distorted pinfire effect in which a bushy of peacock's tail design can be seen.
• Rainbow; pastel irisation tints closely arranged in successive curving bands which merge into each other accross the stone.
• Ribbon; narrow, parallel stripes of alternating colours. Similar to abanderada, but straighter and narrower.
• Rolling Flash; a colour flash which rolls from one side of the stone to the other as it is turned.
• Scotch Plaid; refers to a green-blue effect in black opal.
• Star; a very rare star pattern caused by a particular orientation of diffraction points along fault planes in the opal.
• Starflash; small points of colour forming a speckled star pattern.
• Straw; a pattern resembling flat straws irregularly overlapping one another.
• Sunflash; colours are only visible in very strong light. This type of opal cannot be classified as a gem.
• Tree or Fern Pinfire; elongated pinhead-sized colour units which give an impression of foliage.
• Twinkle; pinfire pattern in which the colour units are separated, giving a similarity to stars in the night sky.