Coolabah, often spelled Coolibah, refers to several species within the Eucalyptus genus, primarily Eucalyptus coolabah and Eucalyptus microtheca, native to inland eastern Australia, including western New South Wales, central South Australia, western Queensland, and parts of the Northern Territory and Western Australia. These trees, part of the Myrtaceae family, grow to 20–50 feet tall with trunk diameters of 2–3 feet, thriving on heavy-soiled, occasionally flooded plains and along intermittent streams where water flow is too sporadic to support species like the river red gum (Eucalyptus camaldulensis). The name "coolabah" originates from the Indigenous Australian Yuwaaliyaay word gulabaa.
The heartwood of Eucalyptus coolabah ranges from orangish-pink to a rich, dark reddish-brown, often seen in burl form with swirling, intricate patterns that make it highly prized. In contrast, Eucalyptus microtheca tends to have darker, greyish-brown to nearly black heartwood, sometimes with an olive cast and white mineral deposits in the pores. The sapwood of both is greyish-white, sharply distinct. The grain is generally interlocked with a fine texture, and the wood has a moderate natural lustre.
Coolabah has a density of 900–1,100 kg/m³, making it one of the hardest eucalypts in Australia, with a Janka hardness of 3,730 lbf (16,590 N). This extreme hardness, combined with its interlocked grain, makes it challenging to work—tearout and tool blunting are common, requiring sharp, carbide-tipped tools. It’s highly durable, with anecdotal reports of excellent resistance to termites and decay, though formal test data is lacking. Its oil content can interfere with gluing, so surface preparation with a solvent is advised. The wood finishes well, polishing to a smooth, high-gloss surface that highlights its figuring.
When worked, Coolabah has a mild scent, though Eucalyptus microtheca can emit an unpleasant odour when green, which fades upon drying. It’s primarily used for turned objects, knife and gun grips, inlays, and small specialty items like pens or bowls. Non-burl wood has been compared to lignum vitae for hard-wearing applications like bearings. Indigenous Australians historically used it for spears, fire-making tools, message sticks, and coolamons (wooden dishes), also sourcing water from its rootwood.
Coolabah is not listed on CITES Appendices, but Eucalyptus coolabah is considered near-threatened by the IUCN, close to qualifying as vulnerable due to habitat pressures, though it doesn’t yet meet endangered criteria. Its availability is limited, often sold as burl blanks, and prices are high, comparable to other Australian burls. In the UK, it’s valued for bespoke woodworking where its durability and unique patterns can be showcased, but its scarcity and workability challenges make it a niche choice.