Wood Fossil Opal
Wood fossil opal also called opalised wood is ancient organic material where the original wood structure has been replaced by silica over millions of years. The cellular pattern of the original wood is preserved in opal, creating a stone that is simultaneously a gemstone and a fossil. All material in this collection is natural Australian opalised wood, untreated.
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What wood fossil opal actually is
Opalisation of wood occurs when silica rich groundwater percolates through decaying wood structure, slowly replacing the organic material with silica over millions of years. What remains is a silica replica of the original wood, preserving cellular structure, grain and in some cases growth rings.
The result is unlike any other opal. The internal structure of the stone tells you it was once living wood.
Color in wood fossil opal
Not all opalised wood shows play of color. Much of it is common opal; translucent to opaque silica without the diffraction that produces spectral fire. The listings in this collection are selected for pieces that show genuine color play. Where a piece is common opal without play of color, this is stated in the listing.
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Wood Fossil Opal FAQs
What is wood fossil opal?
Wood fossil opal is ancient organic material where the original wood structure has been replaced by silica over millions of years. The cellular pattern of the wood is preserved in opal, making it both a gemstone and a natural fossil. It is also called opalised wood.
How does wood become opal?
Silica rich groundwater slowly fills the decaying cellular structure of wood. Over millions of years, the organic material is replaced by silica. What remains is an opal replica of the original wood, sometimes preserving grain and cellular detail.
Does wood fossil opal show color fire?
Some does, some does not. Opalised wood that contains precious opal will show color play. Common opal without this structure will not. Listings at Opal Galaxy that contain color play are selected specifically for that quality. Where a piece is common opal, this is stated in the listing.
Is wood fossil opal suitable for jewelry?
Smaller pieces with strong color play are sometimes cut into cabochons for pendants and rings. Larger specimens with visible fossil structure are more often displayed as natural mineral specimens.
Is opalised wood the same as petrified wood?
They are related but different. Petrified wood is organic material replaced by minerals. Opalised wood is specifically wood replaced by opal silica. Not all petrified wood is opalised, and not all opalised wood shows the play of color that makes it a precious gemstone.