It looks like a G. pratense seedling.
I'd guess that whoever sent you the seed had her G.Orion near a pratense and the bees did some pollen transferring.
Prolific flowering geraniums are always a bonus.

Thank you Maggiepie...it is indeed a G.pratense. I found a site which identifies seedlings by leaf, rather than by flower and that's how I nailed it down. However, as you said, the bees must have been doing their work because I cannot find any pic. of a pratense with this flower colour. The first flower was almost transparent white, but in it's third year, it is definitely pale pink, and very appealing. Thank you again.
Northerner.

'Orion' is a progeny of 'Brookside'. which itself is a hybrid between pratense and clarkei 'Kashmir Purple'. The seed you received was from 'Orion' (one parent) but the other parent could have been Orion or another geranium growing nearby. That is why your flower is not blue like 'Orion'. 'Orion' leaves look like pratense ones, because it is a pratense descendant.

Here is a link that might be useful: 'Orion' pic and leaves

Thanks for the clarification, Ontnative. I started growng these beautiful plants about 3 years ago in memory of Mother, who was quite a gardener herself. I now have about 5 different varieties and am trying to identify them so it's best to have all the knowledge I can. Now I know this plant can produce many surprises depending on how Mother Nature decides to do her work. Always something to look forward to.

Happy to be able to help with this background info., northener. I collect (and grow) lots of hardy geraniums. I find them very addictive, and as a group are very tolerant of less than perfect growing conditions, i.e. part shade and somewhat dry clay. They are also great "blenders" and fit in with so many other flashier perennials.

I have a very similar geranium that appeared in my amongst the 'Brooksides" in my garden a couple of summers ago and this year has spread around. I am assuming a cross between Brookside and G.pratense however it is much tidier and less floppy than the other G.pratenses that I try to pull out before they reseed too prolifically.
Leo

Hi Leo: I am happy to know that these plants reseed. I have been trying to save seeds, but have only managed to save a very few - you know how good they are at propelling their seeds before you can get them. I would not mind having a patch of them since this plant is doing quite well in a part shade location. Thanks for the 'heads-up'.