Where a side table goes, and why its size is different
A side table is not a small coffee table. Its job is to sit within reach of someone already seated, so its height is measured from the sofa arm, not the floor: level with the arm, or 2–5 cm below. A table taller than the arm makes you lift your shoulder every time you set down a cup.
Typical widths run 30 to 50 cm. Under 30 will not hold a cup and a book together; over 50 starts eating walking space.
Beside a bed
A marble side table beside a bed is more practical than it looks: stone is unbothered by a hot cup or by the condensation ring that permanently marks wood. Set the surface level with the mattress or slightly above.
The accent piece in an empty corner
An empty corner in a living room, or the end of a hallway, is the best place for a strongly figured onyx or marble piece. Here the piece does not need to be practical so much as seen: a sculptural base, stone with clear veining, or translucent onyx lit from within.
Onyx and light
Onyx is semi-translucent — put light behind it and it passes through, showing the layers. That is why an illuminated onyx table looks like a different object at night than it does by day. Practically: onyx is a little softer than marble and suits pieces that are looked at more than they are worked.
Pairing with the rest of the room
The stone in a side table does not have to match the coffee table. The easier and better-looking approach: keep the bases consistent — wood with wood, metal with metal — and let the stone differ. Matching everything exactly makes a room look bought in one go.