The Black Locust or False Acacia: Origins and Identity

The black locust (Robinia pseudoacacia) is a fast-growing tree native to the Appalachians and the Ozarks in eastern North America. Introduced to Europe in the early^17th century—notably to France by Jean Robin, the king’s botanist, after whom it is named—it has naturalized in many temperate regions. Known in France by the common name of acacia, it is in fact not botanically related to the genus Acacia. It is a fully indigenous French timber, found particularly in secondary forests, forest edges, and hedgerows. Its longevity, natural strength, and mechanical properties have earned it a prominent place in the trades of lumber, cooperage, wheelwrighting—and more recently, artisanal cutlery.

Properties and Technical Characteristics

Black locust wood is one of the hardest among European and naturalized species. Its Janka hardness is approximately 1,710 lbf [À VÉRIFIER], which places it above oak and close to American walnut. Its density generally ranges from 0.72 to 0.80 g/cm³ [À VÉRIFIER], giving it an excellent strength-to-weight ratio.

Color and appearance

The heartwood of black locust has a yellow to yellow-greenish hue, sometimes honey-colored, which darkens slightly over time and with exposure to light. The sapwood, which is lighter and clearly distinct, is generally removed in cutlery pieces. The grain is fine to medium, with straight or slightly wavy fibers, which makes it easy to work with cutting tools.

Stability and natural durability

Black locust is classified as natural durability class 1-2, the highest category for a European wood. It is naturally resistant to wood-decaying fungi, wood-boring insects, and prolonged moisture—without requiring any prior surface treatment. This property makes it particularly well-suited for outdoor knives, heavily used kitchen knives, and any situation where the handle is exposed to moisture cycles.

How to choose black locust for your knife?

Black locust is suitable for a wide range of projects, from hiking knives to chef’s knives and handcrafted fixed-blade knives. Here are the criteria to consider:

• Outdoor or wet use: black locust is one of the best choices thanks to its natural water resistance—no need for extensive waterproofing.
• Knife-maker’s skill level: The wood is firm but workable with a file, plane, and joinery tools. It’s suitable for both beginners and experienced crafters, provided you use well-sharpened tools.
• Finish: It responds well to oils (linseed, tung), natural waxes, and varnishes. Its surface polishes easily to a satin or glossy finish, depending on preference.
• Combination with blades: its warm hue pairs naturally with weathered carbon steels, Damascus steel, and brushed stainless steel. It provides an elegant contrast without visually overwhelming the overall design.
• Format: Mercorne offers pre-cut handles (ready to be adjusted) and raw blocks for projects requiring custom geometry.

Mercorne and black locust: 34 years of selection

At Mercorne, black locust has been part of our catalog since the company’s early years. Our selection prioritizes pieces with a uniform grain, free of structural defects, and sourced from heartwood to maximize the wood’s natural durability. Each batch is inspected before being stocked. Handles and blocks are cut in our workshop in France, allowing us to guarantee precise and consistent dimensions for every order. Same-day shipping for orders placed before 1 p.m., returns accepted within 15 days, free shipping on orders over €90.

Frequently Asked Questions About Black Locust in Cutlery

Is black locust truly water-resistant without treatment?

Yes. Black locust is classified as having a natural durability rating of 1-2, meaning it resists fungi and moisture without prior chemical treatment. A finish with linseed or tung oil is still recommended to prolong the aesthetic appeal, but it is not essential for protecting the wood itself.

What is the difference between black locust and the acacia sold in supermarkets?

In France, the term “acacia” almost always refers to black locust (Robinia pseudoacacia), not true African or Australian Acacia. At Mercorne, we use the exact botanical name to avoid any confusion. The black locust we offer is a temperate species, naturalized in France, distinct from tropical acacias in terms of density and color.

Can black locust be stabilized?

Black locust generally does not require stabilization: its natural density and low porosity make it relatively impervious to resins. Attempts at stabilization yield variable results depending on the batch. If you are looking for stabilized black locust for a specific project, please feel free to contact Olivier—he will guide you toward the most suitable solution.

Is black locust difficult to work with?

Its hardness requires well-sharpened tools, but black locust poses no particular difficulty when sanding, filing, or turning. It works well by hand and with machines. Its straight grain minimizes the risk of tearing during shaping, making it a pleasant material to work with even for a novice knife maker.

Is black locust a protected species?

No. Black locust is not subject to any CITES regulations or export or trade restrictions. It is a naturalized species in Europe, available in large quantities and sustainably cultivated in many regions of France.