1kg Tantalum Cube (~39.2mm)

Yes. Each metal cube is a solid piece of the material stated in its specifications, rather than a hollow shell or plated object. That matters because the point of the cube is to make properties such as density physically tangible: equal-sized cubes in different metals can feel dramatically different in the hand.

Use the dimensions in the individual product specifications as the reference for that cube. Each cube is machined as a precise geometric object with chamfered edges, so the faces are flat and the corners are comfortable to handle.

That depends on the metal. Copper develops a patina, a unique darkening of the material which makes every piece special. Titanium, tantalum and niobium change very little. Keep a cube clean and dry if you'd prefer to hold on to its original look.

For routine care, wipe the cube with a clean, soft cloth and avoid abrasive cleaning that could alter the finish. If the surface has changed naturally, particularly on copper, decide whether you want to preserve that patina before using any metal-cleaning product.

Because density is mass packed into a given volume. Two cubes can have exactly the same dimensions but contain very different amounts of mass because their materials have different densities. Comparing equal-sized cubes is one of the simplest ways to experience that material property directly rather than as a number in a table.

Tantalum is highly dense, so it does not need much volume to reach approximately one kilogram. That mass fits into a cube roughly 39.2mm on each side. Compare it with a one-kilogram cube of a lighter metal and the tantalum version will occupy considerably less space, even though the two objects register the same mass on a scale.

A kilogram is substantial but manageable for most routine handling, and the roughly 39.2mm dimensions give you a compact object to grip. Its density can make the weight feel surprising because the cube is smaller than you might associate with one kilogram. As with any dense metal object, place it carefully on suitable surfaces rather than judging it by size alone.