Opal Words

Opal terms:

Opalfire refers to the play of color spectral display which appears to dance inside a precious opal as it is moved in the presence of a light source. This display may take a wide variety of forms, from tiny pinpoints of color to a broad sheet covering the entire face of the stone. From pinfire to broadflash, opal's color display is ever different. No two opals look the same. Matching stones may sometimes be cut from a single large block of opal, and match sufficiently for earrings or an entire set of jewely pieces, but this is rare and expensive in high quality opal. The most common pattern is flashfire, a general term meaning a cluster of flakes of single or multiple colors.

Flagstone refers to a specific opal pattern of color display. It consists of irregularly shaped blocks of color which fit together with adjacent blocks to show a solid display of color. There may be a line of potch or precious color along the seams between blocks, but this spiderweb effect is not always present.

The blocks of color may all be relatively the same hue or they present a rainbow roll across two or more colors of the spectrum, sometimes rolling through a full rainbow. The color may roll across the block until it is full, or the color may appear to jump from block to block as the stone is moved. Each of the individual blocks or cells is called a flag or a flagstone.

This example shows a single flag shining with a bright green display. The spider webbing can clearly be seen in this example, delineating the individual flags. The green fire will jump from flag to flag as the stone is moved. The whole stone has a purplish-blue jelly color, but only the green moves from flag to flag.

... This stone shows the rainbow flagstone effect, as the color within a single flag will change as the stone moves. Here (left) a blue creeps up into the green at bottom and yellow orange is breaking through the red of the block above. In the right photo, the blue has taken over the entire green flag, except for an edging of the green color outlining the flag.
The adjacent triangle of color which extends to the top tip of the stone is pure red in the left photo, but is being overtaken by green followed by a pure spectral blue in the photo on the right.

......This Lightning Ridge opal shows very bright rainbow flagstones. The top left pic shows a large flag rolling through red, orange and yellow. The pic above right shows a single flag split between blue and green as the color rolls across the cell. Spiderwebbing is present, but not very prominent in this opal.

Here a single flag displays both blue and green fire.

Green, blue and yellowish orange color flags.

This is a very lively display as the color leaps from flag to flag. Perfect for a ring stone on a busy hand. Spiderwebbing is evident in this opal's flagstone display.