The hardness of wood is a measure of how hard, strong, dense and durable a particular species of wood is. Not all woods that are hard are necessarily durable or strong, but it is true in most cases.
If you are looking to know more about the hardness of timber, what makes some wood species harder than others, and which are the hardest wood in the world, here’s everything you need to read.
What is the Hardness Test?
In order to determine the hardness of a particular wood species, a special test is recommended by experts. It is called the Janka Hardness Test.
The Janka wood hardness test involves pushing a steel ball of 0.444” diameter into the wood such that exactly half the ball’s diameter gets into the wood. The force (pound-force) required to do the job is the Janka rating or hardness rating of that wood.
Which is the Hardest Wood on the Planet?
In terms of Janka hardness rating, Quebracho (Quebracho Colorado, Red Quebracho) with a Janka rating of 4,570 lbf (20,300 N) is considered the hardest wood in the world. Source: wikipedia
Lignum vitae (Guayacan, Pockholz) with a Janka rating of 4,500 lbf (20,000 N) is the second hardest wood in the world. However, it is often considered the hardest wood because of its massive popularity.
One thing you should know about woods is that the harder they are, the more difficult they are to work with. Because of high density, harder woods are not always practical as they may be very difficult to handle, carry, transport, and work with. This is why a more practical question to ask yourself, when buying wood, would be: how much hardness is hard enough for your project?
Why are Some Wood Species Harder than Others?
The hardness of wood has to do with its structure. The more complex the wood structure, with tightly interlocked grain, the harder the timber. Here are some common characteristics of some of the hardest woods:
- Close, interlocked grain
- Slow-growing (slow growth period)
- Very high density
The density of the wood is the primary factor to affect its strength and hardness. More dense woods with tightly situated growth rings are often very hard.
Lignum vitae, for instance, is so dense that it can easily & quickly submerge into the water.
Top 10 Hardest Wood in the World
Here’s all about the top 10 hardest wood species in the world.
Quebracho comes from the Spanish term “quebrar hacha,” which translates to “axe breaker.” This says a lot about the wood’s hardness. It belongs to the Schinopsis genus, which is known to produce some of the hardest and heaviest woods in the world.
Quebracho trees are found in tropical South America and are about 30-50 ft (9-15 m) tall with a 1-3 ft (.3-1 m) trunk diameter. The average dried weight of the wood is 77 lbs/ft3 (1,235 kg/m3), which is considered huge in this industry. The Janka rating of Quebracho is around 4,570 lbf.
Quebracho heartwood is light to medium reddish brown and the sapwood is pale yellow. The texture is fine & uniform and the grain is irregular and interlocked. Quebracho is considered very durable in terms of weathering and insect resistance. It is difficult to work with due to its high density. Common uses include heavy construction, furniture, and railroad cross-ties.
2. LIGNUM VITAE
Lignum vitae is a Latin term, which means “tree of life.” It is called so because of its amazing medicinal uses.
The wood originates in Central America and northern South America and the trees are about 20-30 ft (6-10 m) tall with a 1-2 ft (.3-.6 m) trunk diameter. The average dried weight of
Lignum vitae is 78.5 lbs/ft3 (1,260 kg/m3), which is why it is often considered harder than Quebracho wood.
Lignum heartwood is dark greenish-brown to nearly black. The grain is interlocked and the texture is very fine. The wood is very durable and resistant to attack by insects. It can be difficult to work with. Common uses include handles, bearings, pulley wheels, mallet heads, and bushings.
With a Janka rating of 4,270 lbf (18,990 N), Gidgee is the third hardest wood in the world. It is native to Australia and has an average dried weight of 72 lbs/ft3 (1,150 kg/m3).
The heartwood of Gidgee is medium to dark reddish brown and may occasionally have darker streaks. The sapwood is yellow and easily distinguished. Common uses include wood weapons, gadgets, firewood, etc.
The fourth hardest wood in the world has an appearance like the skin of a snake. It is limited in supply and has great demand, which makes it one of the costliest woods in the world.
Snakewood is sourced from the Coastal regions of northeast South America. It has a 75.7 lbs/ft3 (1,210 kg/m3) average dried weight and a 3,800 lbf (16,900 N) Janka rating. The heartwood colour is reddish brown, the grain is straight, and the texture is fine. Snakewood is very durable in terms of insect attack. Uses include veneering, tool handles, inlay, violin bows, and turned objects.
Verawood is prized for its beautiful looks and low price. It is obtained from Central America and northern South America. The Janka rating of Verawood is 3,710 lbf (16,520 N) and the average dried weight is 74 lbs/ft3 (1,190 kg/m3).
Verawood looks incredible in its unique feathered pattern. The heartwood colour is pale yellowish or greenish dark brown or nearly black. The grain is straight and the texture is fine & even. It is a very durable wood and suitable for exterior uses. Other applications include tool handles, bearings, boatbuilding, mallet heads, and heavy construction.
6. CAMEL THORN
Camel thorn, also called Giraffe Thorn, is a Southern African wood with a 3,680 lbf Janka rating and 1,185 kg/m3 average dried weight. The heartwood of Camel thorn is dark brown and the sapwood is yellow. The texture is uniform medium. It is a durable wood with good insect resistance. Uses include fence posts, turned objects, and firewood.
7. AFRICAN BLACKWOOD
African Blackwood is the hardest wood produced in Africa. It is almost completely black with very fine grain. The sapwood is pale yellow. The texture is even. The Janka rating of African Blackwood is 3,670 lbf (16,320 N) and the average dried weight is 79 lbs/ft3 (1,270 kg/m3). It is considered very strong and durable and is resistant to decay and insects.
Uses of African Blackwood include musical instruments, carving, tool handles, and inlay.
8. BLACK IRONWOOD
Black Ironwood or Leadwood is found in Central America. It is heavy with an average dried weight of 1,355 kg/m3 and strong with a Janka rating of 3,660 lbf. The heartwood is often brownish-red but can also come in orange and violet hues. The grain is straight and the texture is very fine.
Black Ironwood is very durable in terms of resistance to decay and termites. It is used for veneering, firewood, and turned objects.
Katalox, commonly called Mexican ebony, is a black hardwood with a 3,660 lbf Janka rating and a 1,150 kg/m3 average dried weight. It is found in Southern Mexico, Central America, and northern South America. The heartwood is dark brownish or almost black, and the sapwood is pale white. The grain is usually straight and the texture is fine.
Katalox is very durable and has high resistance to decay and termites. It is used for fine furniture, guitars, inlays, cabinetry, turnings, and parquet flooring.
10. CURUPAY (CEBIL)
Cebil or Curupay is a hardwood found in Argentina, Brazil, and Paraguay. The reddish brown heartwood with brown/black streaks looks similar to rosewood. It has interlocked grain and a fine uniform texture. Cebil is very durable in terms of termite resistance. Uses include flooring, furniture, turned objects, and exterior construction.
White Knight Consulting is a wholesale supplier and manufacturer of premium construction-grade timber in the UK. If you need help selecting or buying the best wood at the right price for your project, do contact us right away.