Oil for top up

[52classic]

This is where I admit to being a dinosaur! Always used mineral oils in my cars. Nothing special, non branded fleet stuff usually. My 'modern' (02 CR-V actually) needs a top up but since I haven't changed the oil since buying it I don't know what's in there.

Can I identify synthetic, semi synthetic or mineral? If not, are they mixable for top up purposes?

Finally, what choice for an oil change as part of my spring service later on?

Any other advice about current practice to bring me into this century would be very welcome!

[52classic]

Semi synth it is then. Thanks for your help gents.