Fossilized Wood (Silicified)
Petrified Wood
Petrified wood isn't a mineral at all — it's fossilized wood in which every trace of the original organic plant material has been replaced by silica through a process called permineralization, cell by cell, over a very long period. Its color has no relationship whatsoever to the tree's original living color, since 100% of the organic material is gone; every hue comes entirely from trace minerals present during the silica-replacement process.
The geology — what Petrified Wood actually is
- Mineral class
- Fossil (originally wood; fully replaced by silica, usually chalcedony/quartz, occasionally opal)
- Chemical formula
- SiO2, replacing the original cellulose and lignin plant structure entirely
- Crystal system
- Trigonal microcrystalline (or amorphous if opalized) — though the original wood grain is preserved as fossil texture rather than as any crystal structure
- Mohs hardness
- 6.5 to 7 (governed by the replacing quartz, since none of the original organic wood remains)
What causes the color: Trace minerals present during silicification determine the color entirely — iron oxides for reds, browns, and yellows, manganese oxide for blacks, blues, and purples — with no connection at all to how the living tree originally looked.
How it forms: Forms when wood is buried rapidly, often by volcanic ash or sediment, in conditions that limit oxygen and decay, allowing silica-rich groundwater to gradually replace the wood's cellular structure cell-by-cell over an extremely long period, preserving the original grain and growth rings in stone even though no organic material survives.
- Petrified Forest National Park, Arizona, USA (one of the most famous concentrations in the world, roughly 225 million years old)
- Madagascar
- Indonesia
Treatments & imitations: Rarely treated — the natural fossilization process and resulting color are left as-is.
Real vs. fake: Genuine petrified wood shows authentic preserved wood grain, bark texture, and sometimes visible growth rings under magnification — a fossilized cellular structure that's extremely difficult to convincingly fake. Resin or dyed-stone imitations sold as 'petrified wood' lack this specific fossilized cellular detail entirely.
The tradition — how people use Petrified Wood
Historical use: Petrified wood has been recognized and valued across many cultures wherever found, given how visually striking the combination of wood-like texture and stone hardness is, and various Indigenous peoples near major deposits have used it decoratively and, in some regions, ceremonially, though its specific modern metaphysical framing is a more recent, contemporary layer on top of that broader recognition.
Metaphysical tradition: At the root chakra, modern crystal-healing tradition ties petrified wood to grounding, patience, and ancestral connection, drawing directly on its literal deep-time origin.
How to use it: Frequently kept as a display piece, or worn as jewelry once cut and polished into cabochons or beads.
Cleansing & care: Nothing special is needed here beyond a plain water rinse now and then — Mohs 6.5-7 handles everyday wear and tear without issue.
Frequently asked questions
How can wood grain and growth rings still be visible if none of the original wood remains?
The silica replacement happens slowly enough, cell by cell, that it faithfully copies the wood's original microscopic structure before that structure has a chance to collapse or decay — essentially a natural molding process at a cellular scale, similar in principle to how a plaster cast can preserve fine surface detail of an object that's since been removed, except here the 'cast' is silica and it happened underground over an extremely long span of time.
Can you tell what species of tree a piece of petrified wood came from?
Sometimes, yes, but not from color — paleobotanists identify the original tree species by examining the fossilized cellular structure itself (cell arrangement, ring spacing, and other microscopic anatomical features that silica replacement preserves faithfully), the same general approach used to identify living wood species, entirely independent of whatever color the trace minerals happened to leave behind.
How old is most petrified wood?
It varies by deposit, but some of the most famous concentrations, like Arizona's Petrified Forest National Park, are around 225 million years old — a genuinely deep-time fossil record preserved in remarkable structural detail.
Related crystals
Obsidian
Volcanic Glass
Obsidian isn't technically a mineral at all — it's a mineraloid, volcanic glass that cools too fast for atoms to organize into any crystal structure, which is why it has no defined chemical formula and no Mohs-scale crystal system in the way quartz or feldspar do. That same rapid, structure-free cooling is what gives obsidian its razor-sharp conchoidal fracture, a property humans have exploited for stone tools and ceremonial blades for tens of thousands of years, right up through surgical scalpel blades used in some modern operating rooms today.
Smoky Quartz
Quartz Family
Smoky quartz gets its brown-to-black color through the same broad family of chemistry as amethyst's purple — trace-element impurities forming color centers under natural irradiation — but with aluminum standing in for amethyst's iron, producing smoke rather than violet. Much of the very dark, nearly opaque smoky quartz sold commercially today isn't purely a product of slow natural geology at all: clear quartz is routinely irradiated artificially to darken it, a disclosed industrial practice that speeds up a color change nature would otherwise take far longer to produce.
Red Jasper
Chalcedony Family
Red jasper is an opaque, iron-rich variety of chalcedony (microcrystalline quartz), and that opacity is really the defining feature separating jasper from its close cousins: where carnelian is translucent enough to glow when backlit, jasper carries a much denser load of mineral inclusions that block light from passing through at all, even in a thin slice. Both get their red-brown color from iron oxide, but jasper's higher inclusion density is what gives it a solid, earthy, almost stone-like opacity rather than carnelian's warm glow.
Mookaite
Jasper (Chalcedony Family)
Mookaite has a genuinely unusual origin story among the jaspers on this site: it's silicified radiolarite, meaning its mottled red, yellow, purple, and cream pattern comes from ancient seabed sediment made almost entirely of microscopic radiolarian skeletons — single-celled marine organisms — that was gradually replaced by silica over millions of years. It's sourced from exactly one place: Mooka Creek station in Western Australia, which also gives the stone its name.
Where to buy Petrified Wood
We don't have an active affiliate program live yet, so instead of a placeholder link, here's the same buying guidance we'd give a friend.
Specialty mineral dealers & gem shows
The most reliable source for anything beyond common tumbled stones — sellers who specialize in minerals tend to disclose treatments and localities unprompted, because their repeat customers ask.
GIA/AGS-affiliated jewelers
For cut gemstones meant for jewelry (not raw specimens), a seller who can produce or reference an independent lab report (GIA, AGS) removes almost all of the real-vs-fake guesswork.
Marketplace sellers with a track record
Etsy and similar marketplaces host genuine small mineral dealers alongside mislabeled resin castings — check seller reviews specifically for photos of received items, not just star ratings.
Local rock & gem shops
Being able to handle a piece before buying lets you apply the weight and hardness checks described on each stone's own page — something no photo can substitute for.
Whichever seller you choose, ask directly whether the stone is natural or synthetic, and whether it's been treated (heated, dyed, irradiated) — a straightforward answer is the single best signal of a trustworthy seller, more useful than any star rating.
Some links on this page are affiliate links — if you buy through them, GemGlow may earn a small commission at no extra cost to you. We only link to sellers we'd genuinely recommend.
Sources and factual basis for the geology above: see our methodology.