Opals come in a variety of colors, and they range from opals to transparent. The most desirable opus are known as the precious opals. They have a special iridescent quality as you move the opals under the light it shows a spectrum of colors which word provides the best context clue for the meaning of iridescence.

The word "spectrum" provides the best context clue for the meaning of iridescence.

The word "spectrum" provides the best context clue for the meaning of iridescence.

To determine the best context clue for the meaning of "iridescence" in relation to opals, we can look at the sentence that describes how opals exhibit a spectrum of colors when moved under light. This description suggests that iridescence refers to the play of colors or the phenomenon where an object reflects or refracts light to produce a shifting range of colors.

The word "spectrum" provides the best context clue for the meaning of iridescence in this case. A spectrum refers to a wide range or sequence of colors that are ordered based on their wavelength. In the context of opals, the spectrum of colors visible when moving the stone under light is indicative of their iridescence.