Is this solid 14k rose gold?

No. It is 14k rose gold plated, so the gold layer sits over a base metal. Solid 14k rose gold chains cost far more and keep their color indefinitely; this one will eventually show wear at high-friction spots.

How wide is the chain and what does it suit?

It is 2 mm wide, which is a medium-weight chain. That is thick enough to carry a small pendant and to layer with a finer chain, but not a chunky statement look.

Can I wear it in the shower or pool?

Better not. Water, soap, chlorine and sweat speed up plating wear and can dull the rose tone. Take it off before showering, swimming and workouts.

What clasp does it have?

It closes with a lobster clasp, which is generally more secure and easier to work one-handed than a spring ring.

Will the rose gold color match other rose gold jewelry?

Rose gold plating varies by maker, so the tone may sit slightly pinker or warmer than solid 14k rose gold pieces. It layers most cleanly with other plated rose gold items.

How should I clean it?

Wipe it with a soft dry cloth after wear and store it in a dry pouch away from other chains. Skip abrasive polishes and ultrasonic cleaners, which can strip plating.