by Eric Meier

The most common test for testing wood hardness is known as the Janka hardness test. The actual number listed in the wood profile is the amount of pounds-force (lbf) or newtons (N) required to imbed a .444″ (11.28 mm) diameter steel ball into the wood to half the ball’s diameter.

Janka hardness testing

Janka hardness testing

 In practical terms, a helpful question to ask would be: hard is hard enough? A lot of times, especially on floors, the finish will get scratched, when the wood underneath is perfectly fine. (This obviously excludes dents.) In all practicality, a great number of hardwoods are “hard enough” for nearly all residential applications. But, if you’ve simply got to have the hardest lumber around, then this list is for you!


Cebil (Anadenanthera colubrina)

Cebil

(Anadenanthera colubrina)

3,630 lbf (16,150 N)

Also known as Curupay or by the exaggerated name Patagonian Rosewood, Cebil is not a true rosewood. It has a highly variable streaked appearance not too unlike Goncalo Alves.


 Katalox (Swartzia cubensis)

Katalox / Wamara

(Swartzia spp.)

3,655 lbf (16,260 N)

Some pieces can be just about a dark as true ebony, while others are a more reddish brown with black streaks. So much depth in the Swartzia genus, there’s something for everyone!


Black Ironwood (Krugiodendron ferreum) 

Black Ironwood

(Krugiodendron ferreum)

3,660 lbf (16,280 N)

Pieces are very seldom seen for sale, as this tree is too small to produce commercially viable lumber. Like the unrelated Desert Ironwood, Black Ironwood is an excellent choice for small turning projects.


African Blackwood (sealed)

African Blackwood

(Dalbergia melanoxylon)

3,670 lbf (16,320 N)

In some parts of the world, this wood has achieved an almost legendary status. Historical evidence points to this wood (rather than Diospyros spp.) being the original “ebony.”


Camelthorn (Vachellia erioloba)

Camelthorn

(Vachellia erioloba)

3,680 lbf (16,370 N)

Formerly classified as a member of the Acacia genus, this south African hardwood is a tough customer. The wood is stubbornly hard, and the tree is protected by giant sharp thorns.


Argentine Lignum Vitae (sealed)

Verawood

(Bulnesia arborea)

3,710 lbf (16,520 N)

Sometimes called Argentine Lignum Vitae, this wood is a gem: inexpensive, great olive-green color, beautiful feathery grain pattern, and it takes a great natural polish on the lathe.


04 Snakewood (bookmatched)

Snakewood

(Brosimum guianensis)

3,800 lbf (16,900 N)

It’s easy to see what makes Snakewood so unique–its patterns and markings resemble the skin of a snake. Limited supply and high demand make this one of the most expensive woods on earth!


Gidgee (Acacia cambagei)

Gidgee

(Acacia cambagei)

4,270 lbf (18,990 N)

This Australian endemic is both very heavy and very strong. Some pieces are dark enough to be used as an ebony substitute: one that’s even harder than the original article.


Lignum Vitae (Guaiacum officinale)

Lignum Vitae

(Guaiacum officinale)

4,390 lbf (19,510 N)

Widely accepted as the hardest wood in the world–this wood has been listed as an endangered species and is listed in CITES. Consider Verawood as a very close substitute.


Quebracho (Schinopsis balansae)

Quebracho

(Schinopsis spp.)

4,570 lbf (20,340 N)

From the Spanish “quebrar hacha,” which literally means “axe breaker.” Aptly named, wood in the Schinopsis genus is among the heaviest and hardest in the world.


Honorable mentions: Leadwood (3,570 lbf), Brown Ebony (3,590 lbf), Ipe (3,510 lbf), Mopane (3,390 lbf), Burmese Blackwood (3,350 lbf), Kingwood (3,340 lbf).

Other notes:

  • Hardness listings are for woods at a dried weight of 12% moisture content.
  • There are a handful of obscure shrubs and small trees that yield wood which can be extremely hard. However, these species are typically only available regionally, and are never seen by the vast majority of woodworkers, nor are they reliably documented in woodworking publications.

See also:


  • Mark_Kelly

    Allocasuarina Leuhmannii (Buloke)

    • ejmeier

      When someone shows me a credible and verifiable source for this wood’s Janka hardness, I’ll consider adding it.

      • Jace

        I found a site that lists the Janka hardness ;)
        http://www.wood-database.com/australian-buloke/

        • June Brook

          I have a piece of the second hardest wood in the World.It belonged to my late Husband.It is called Lignum Vitae

        • Dennis

          My wood is the hardest in the world

      • Eugene Dimitriadis

        Here it is …..”Wood in Australia”
        Types, Properties and Uses

        by Keith R Bootle (Australian Publication)

        Second Edition
        An excellent technical publication on the more popular Aust. species

        • Eugene Dimitriadis

          Mark is correct. Buloke is among the hardest in Aust by the Janka hardness penetration test,

        • ejmeier

          I do have that book, and I admit that this list needs updating. But I still have my doubts about Buloke’s hardness. I’d be interested to know the source where Bootle got his information. I suspect that the Janka number was either for end hardness (rather than side hardness), or it was for a sample that was drier than 12% MC.

        • Eugene Dimitriadis

          I have no reason to doubt the technical information in Bootle.

          From my experience, data in it has been accurate. Dry Buloke (moisture content not sepcified) is given as > 22 KN, Belah (another dryland casuarina) is given as 20 KN (same as Lignum vitae). Gidgee as 19 KN.

          The say that harness data is an average of radial and tangential sections. Like density and colur, Janka hardness is likely to show some variation as in all species, according to growing conditions.

        • ejmeier

          I don’t dispute that Bootle’s information is credible, but I’ve found that even the most credible of sources can still give a false impression, or pass on typos. For instance, beside the moisture content of the tested wood, and side/end hardness, there’s also the matter of number of samples tested. If an exceptionally hard and heavy specimen was the only piece tested, this would not give an accurate picture of the wood’s AVERAGE hardness.

          The reason I bring this up is because Buloke’s average weight (which I’ve also confirmed myself) is around 1100 kg/m3, which is rather light in comparison to its supposed extreme hardness. There are other Allocasuarina species which are virtually the same weight, with much lower hardness levels (almost half), such as A. torulosa. I’d just like to get to the original source of the data. I’d love to be proved wrong — and I suppose if I can’t, and it comes down to it, I’ll just take his word for it.

          But just consider this: if I list a bunch of endangered or protected Australian woods at the top of this list, everybody and their brother is going to run out and try to source these woods. They will scour the internet for someone willing to scour the Australian landscape in search of these woods. It is just the nature of the beast.

        • cicchis0

          Here is a link to a document that Eugene described in your correspondence on the Top 10 Heaviest Woods page. Whilst it does not cover Buloke (Allocasuarina leuhmannii), it may still be of interest because it covers several hardwoods found in western Queensland, uses sound scientific method, and testing was performed in a nationally accredited laboratory: https://rirdc.infoservices.com.au/downloads/04-132.pdf

          Section 3 covers the mechanical properties, and describes the methodology of the sampling and testing. Table 3.1 on Page 23 (Page 43/242 in the pdf) shows the average air dry (which it defines as 12% moisture content, tested in accordance with AS/NZS 1080.1 (1997)) Janka hardness (average of tangential and radial surface hardness), tested in accordance with BS 373. It includes the following data that may be of interest with relation to this list and/or the individual species pages:

          Beefwood (Grevillea striata): 14.5 kN;
          Coolabah (Eucalyptus coolabah): 16.2 kN;
          Mulga (Acacia aneura): 17.1 kN;
          Gidgee (Acacia cambagei): 17.3 kN;
          Lancewood (Acacia shirleyi): 17.3 kN;
          Red lancewood (Archidendropsis basaltica): 17.9 kN; and
          Ironwood (Acacia excelsa): 18.0 kN.

          I agree that encouraging the harvest of scarce trees is not a good idea, but on the other hand, I really like this site as a reference, and would like it to be as complete and accurate as possible for those species that are commercially traded, even in limited numbers and small pieces, such as for use as knife handles.

          Regards,
          Soren

        • citizen6

          I tried to get this wood to make marital arts weapons years ago; that dog don’t hunt. I had a connection in Australia. Seems decades ago they made fence posts out of it but know it is protected. At the time there were a few pieces to be found but not what I needed. I usually use Lignum Vitae but it is very hard to get.

  • tomfordc

    Bubinga and Purple Heart are up there as well

  • Dru

    What wood is suitable high temp (car exhaust) heat insulation?

  • This wood is giving me wood. Makes me wish I had a cabin made of ebony.

  • sjambok

    Thanks this is fascinating. Can you insert where they are from?

  • Sandro

    Can’t believe this! I shamefully cut some quebra hacha at home in Puerto Rico when I was in my teens. We used the wood for burning and fencing . I still remember the axe hitting the tree and rebounding like nothing I ever experienced before. I long forgot this until now when I read this list of top ten hardest woods. I thought that our name for the wood was merely a colloquial, common name. I knew that the wood was very dense and hard but never thought it made the list. Can I use it to make an electric guitar, after drying??

    • ejmeier

      I’m sure it’d be fine to use for a guitar, but it’d be quite heavy if it were solid. Best to use it as a top lamination.

  • Eugene Dimitriadis

    I agree Marcus

  • Swaggy_Swordsman

    does anyone know where i can buy black ironwood?

  • Erik Larsen

    I fully support Eric Meier’s

    position. If one does not perpetuate the criteria applicable to list the hardest woods,
    anyone can present a Janka test and demand it to be
    included on a list. Controlled
    and multiple test must be done.

  • Malakye Lord

    Not sure how hard it is but nightcap wattle which is really quite rare and only found in one national park. I was lucky enough to have some from a property that bordered the park and I couldn’t route more than a few inches before the bit was buggered. I used about 20 bits on a round table no more than a metre across.

  • Wade Patton

    Yes, but none of those grow around here. Osage orange does, and I use it for show or for durability when weight is of no concern.

  • Jon Denyer

    Still an amateur woodworker, so excuse what my be a silly question, which of these top 10 woods would withstand the use of being a riser for a take down bow? The limbs are made of ash, have tried oak and other common hardwoods to the UK but none can stand the strain. Many thanks Jon

  • Faiz Amar Balaydin

    Does anyone know a company which sells beand new frame which cut trees with 1 m or 1.2 meter diameter. And does anyone know a company with the best bandsaws sawmill.

  • JerBear

    Have you ever seen anything for Keawe — Prosopis pallida ?
    or
    Mountain mahogany — Cercocarpus montanus ?

    Both are very hard and won’t float in water. Neither is a commercial wood.

  • Dave G

    There is an archived listing of the top 125 hardest and softest woods, along with a good description of hardness testing by Brinell {steel ball}, Chalais-Meudon {Monnin} {steel cylinder}, Janka {steel ball}.

    http://archive.is/20120904022306/www.morlanwoodgifts.com/MM011.ASP?pageno=207

  • Pablo Li

    So Australian Buloke is not the hardest wood? I’ve been working with quebracho, after planing 10 minutes the sole of my plane is destroyed as well as the blade haha