Short answer: Check the edges and end grain first, then look at the underside, drawers and back. Solid wood shows grain that wraps continuously over the edge and matching wood underneath. Veneer shows a separate layer at the edge, a different material underneath, and often chips or lifting where the thin skin has come away.
Look at the edges and end grain
On solid wood, the grain flows continuously from the top, over the edge and down the side. On a solid top, you can often see end grain, the growth rings that match the face figure.
On veneer, the grain stops, changes direction or runs horizontally along the edge. You may see an applied edge band instead of end grain.
Check the underside, drawers and back
Look at the bottom, the back and the drawer bottoms. Exposed particleboard, MDF or plywood show what the core is made of. Veneer often sits on a core of plywood, particleboard, MDF or, on older antiques, solid secondary wood such as pine or poplar.
Solid wood usually shows matching grain on the underside, and the boards run all the way through.
Repeating or mirror-image figure
A repeating or mirror-image figure on a tabletop, such as book-matched or slip-matched grain, usually means veneer. Those patterns come from sheets of veneer cut from the same log and laid side by side. It’s a useful clue, but not proof on its own.
Weight and feel
Solid wood is usually heavier than a similar piece with a veneered surface, because veneer sits on a lighter core. Compare similar pieces, though. Size and species make a big difference, and MDF and particleboard are dense, so a heavy piece is not automatically solid wood.
Why tapping is unreliable
Many people knock on a piece to listen for a solid or hollow sound. That test is unreliable, so don’t rely on it. Use the edges, the underside and the grain instead.
Chips, bubbles and lifting edges
Chipped corners, peeling edges or bubbles often reveal what’s underneath. If you see a different material below the surface, the piece is veneer. Veneer repair covers fixing those chips and lifted edges. A chip in solid wood shows more wood, which can be sanded and refinished.
Laminate and printed wood-look finishes
Laminate and printed “wood-look” paper or foil have a perfectly repeating pattern, no real pores, and a plastic feel. They often peel at the edges. To refresh laminate rather than replace it, see how to refinish laminate cabinet sides. Laminate can’t be carved, and it doesn’t show real grain texture the way wood does.
Labels can be unclear. “Solid wood construction” or “wood products” may mean veneer over a composite core. “All wood” can include plywood. Check the piece rather than relying on the label.
Why it matters before you sand
Veneer limits sanding. Veneer is often about 0.6 mm (1/42 in) thick or thinner, though 19th-century saw-cut veneer could be roughly 1.5 to 3 mm (1/16 to 1/8 in). Sanding through it is common, and deep repairs need patching or re-veneering.
Solid wood can be sanded and refinished more than once, but it moves more with humidity. Veneer on a stable core can be more stable, which is one reason fine antiques often use it.
Before you sand any piece, check it. If it’s veneer, use light sanding and a card scraper, or skip sanding altogether. Painting is another option, as explained in can you paint veneer furniture. Can I just sand varnished wood? covers the sanding limits in more detail, and how to strip varnish from wood furniture safely covers chemical stripping, which may be safer for veneer.
Safety: particleboard and MDF dust can contain formaldehyde-based resins. Wear a mask if you cut or sand them.