Petrified wood can generally get wet with very few exceptions. This natural material is not wood in the traditional sense, but a fossil where the original organic matter has been completely replaced by durable minerals. Because of this transformation, water exposure does not pose the typical threats of rot, swelling, or mold that affect living or dead wood.
The Mineral Composition That Resists Water
Petrified wood is formed through silicification, a process where the original tree structure is completely replaced by minerals. This happens when a fallen tree is rapidly buried, preventing normal decay. Groundwater rich in dissolved minerals, primarily silicon dioxide (silica), permeates the wood.
The silica fills the cellular structure while the organic components (cellulose and lignin) are slowly dissolved and replaced. Over millions of years, often assisted by pressure and temperature, the silica typically transforms into the highly stable mineral quartz.
Chemically, the finished material is essentially a form of quartz, which is hard, dense, and non-porous. Unlike organic wood, which absorbs water and swells, petrified wood is chemically inert to water. The fossilized material will not decay, rot, or warp when exposed to moisture.
Exposure Scenarios and Cleaning
Due to its mineral composition, petrified wood is highly suitable for use in environments with high humidity or direct water contact. It is commonly utilized for outdoor landscaping, such as in garden features or as natural stone accents exposed to rain. Indoor applications also take advantage of this durability, with pieces used as vanity tops, kitchen counters, or decorative accessories in high-moisture areas.
Cleaning Petrified Wood
The cleaning process is straightforward because of its stone-like nature. Since the material is impervious to water, you can safely wash it to remove dirt and grime. The safest method involves using lukewarm water and a mild, pH-neutral cleaner, such as gentle dish soap.
Apply the soapy water with a soft cloth or sponge, then rinse the surface thoroughly with clean water to remove residue. Avoid abrasive scrubbing tools or harsh chemical cleaners, as these can dull the polished finish. Treating it like a polished mineral surface helps preserve its aesthetic qualities.
Cautions Regarding Fractures and Mineral Leaching
While the petrified material itself is waterproof, water can still interact with it negatively. The primary concern for pieces placed outdoors in cold climates involves the freeze-thaw cycle. If the wood has pre-existing cracks, voids, or fissures, water can seep into these spaces.
When this trapped water freezes, it expands, exerting pressure on the surrounding rock. Over many cycles, this expansion can cause existing fractures to widen or lead to new chips and breaks. This is mechanical damage to the structure, not water damage to the fossilized material.
Another consideration relates to secondary minerals within the stone. The rich colors often come from trace elements like iron, manganese, and copper incorporated during fossilization. If a piece is continually saturated, these external minerals may slowly leach out. This leaching can potentially cause rust-colored stains on surrounding surfaces, such as patio stones or indoor carpeting.