What’s In The Box? Playing with color

The most famous precious opal in the US comes from Virgin Valley in Humboldt County, Nevada. Petrified tree trunks buried in volcanic tuffs have developed opals with gorgeous play of color.

Opal held in hand.

In this specimen, white common opal infills large holes, while blue and green precious opal is found in pores preserving the tree trunk’s original grain structure. This specimen is from Richard and Helen Rice’s original family collection.

Have you ever collected opal from Virgin Valley? Where are some of your favorite opal localities?

This is part of our What’s in the box? series.

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2 thoughts on “What’s In The Box? Playing with color

    • Wood becomes “petrified” when the organic woody material is replaced by minerals. This usually happens once the wood has been buried by sand or ash (like the volcanic tuffs of Virgin Valley). Water carrying dissolved minerals percolates through the system and leaves those minerals behind in the wood–just like the white gunk you get from hard water build-up, only much prettier! In this case, the minerals left behind happened to be precious opal.

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