Rainbow cloud over Brazil
© YouTube/Jean Wybson (screen capture)
A Brazilian woman has defied Mother Nature's odds and captured a very rare and ethereal rainbow cloud hovering above Caxias.

The venerable National Geographic proclaims iridescent clouds - as they are scientifically known - are hardly ever seen, and that it's rarer still to snap a photograph of the majestic phenomenon.

But Mar Gómez did the double on Friday, filming the multi-coloured blob of candy floss and sharing the goodness across social media.

It takes a very specific set of circumstances for an iridescent cloud - also called "fire rainbows" or "rainbow clouds" - to form, National Geographic reports.

If you do happen to see one, it will happen late in the afternoon, often paired up with a thunderstorm.

The clouds must be very thin and comprised of very thin ice droplets, which combine to produce the stunning array of colour when pierced with sunlight.

Colours will be vivid, and are similar to the visual experience of seeing oil in a puddle.