Customers ask me all the time whether a wood is "hard enough" for a ring. The honest answer is that almost any hardwood is, but the Janka scale is the closest thing we have to a single number that captures durability. It's useful, with caveats. Here's how it works and where some of my favorite woods land on it.
What the Janka Scale Measures
The Janka test is simple. You take a steel ball, 11.28 mm across, and you press it halfway into a piece of wood. The amount of force it takes to do that, measured in pounds-force (lbf) in the US or newtons elsewhere, is the wood's Janka rating.
That's it. One number, one test. It tells you how resistant a wood is to denting and surface wear. Higher number means harder.
It does not tell you everything. It says nothing about how stable a wood is over time, how it polishes, how it handles tear-out, or whether the grain will fight you while shaping it. Two woods with the same Janka rating can behave completely differently on the bench. I've written about this in The Most Difficult Woods That I Work With if you want to go deeper on why hardness alone is a poor predictor of workability.
Where Some of My Woods Land
A handful of common reference points to anchor the scale: red oak, the standard most US flooring is benchmarked against, sits at around 1,290 lbf. Hard maple is 1,450. For context, balsa is roughly 70.
Now the woods I actually use in the shop.
| Wood | Janka (lbf) |
|---|---|
| Lignum Vitae | 4,390 |
| Snakewood | 3,800 |
| African Blackwood | 3,670 |
| Desert Ironwood | 3,260 |
| Ebony (Gaboon) | 3,080 |
| Olive | 2,700 |
| Purpleheart | 2,520 |
| Bubinga | 2,410 |
| Bocote | 2,010 |
| Ziricote | 1,970 |
| Hard Maple | 1,450 |
| Koa | 1,170 |
| Tasmanian Blackwood | 1,160 |
Lignum vitae is one of the hardest commercial woods you'll come across, and that number is why working it is such a test of patience at the bench.
The Numbers That Aren't on the Chart
A couple of materials I work with don't get clean Janka ratings, and the reasons are worth understanding.
Burl. Burl is one of my most-used materials, and it's also one that the Janka scale can't really describe. Burl wood is chaotic by definition. Hardness varies within a single piece, sometimes dramatically. A section that cuts smoothly sits right next to a section that fights the tool. Reducing burl to one number would be misleading. Amboyna burl, for example, comes from a species (Pterocarpus indicus) that rates around 1,260 in its straight-grained form, but the burl behaves nothing like that.
Black palm. Black palm is a more occasional material in my shop, but it's worth a mention because it doesn't fit the scale at all. It isn't technically a hardwood. It's a monocot, more closely related to grass than to oak. The dark spots are vascular bundles running through a softer matrix, and the density swings between them. A single Janka number for the whole piece doesn't really mean much. That density variation is also why the cheetah-print grain looks the way it does. More on that in our black palm post.
What This Means for a Ring You Actually Wear
For everyday wear, almost any wood above about 1,000 lbf will hold up well with reasonable care. The very hard species like ebony, lignum vitae, and African blackwood are especially forgiving of daily use. Softer favorites like koa take more attention during shaping in the shop, but once finished and oiled, they wear well on the finger too.
What matters more than the Janka rating is how you treat the piece. Take it off before lifting weights or doing heavy yard work, keep it dry when you can, and re-oil it a few times a year. We also offer lifetime reconditioning on every piece we make. Bring it back to the studio and we'll clean it up and refinish it.
A Useful Number, Not the Whole Story
Janka hardness is a good starting point when you're choosing a wood. It's not the finish line. The wood that's right for your piece depends on the look you want, how the grain behaves, and how it pairs with the metal and stones in the design.
If you want to talk through what wood makes sense for a custom piece, book a consultation and we'll walk through samples together.
Janka figures in this post are referenced from The Wood Database and the Bell Forest Products Janka hardness chart.
