Dougal77

This colour is pearl light grey (check the comments on the flickr post the link takes you too for more information about these specific bricks), these bricks are q-parts (parts used by legolands/model shops that never appeared in sets). I suggest selling them straight on bricklink where these pieces are already being sold.

In regards to different q-parts, bricks and plates are easiest to find, it's best to filter all bricks by most expensive and then check if that colour was used. In my experience 1x3s and 1x4s have so many q-parts but check the other variations of the brick to see if the variation had the colour. For instance the 1x4 (3010) has glitter trans-purple bricks fo sale, these seem good as they never appeared in set's but 3066 did appear in set's with that colour. The only UK store I've found is spectrum-bricks, I've ordered from them many times and there bricks are great. Fantastic bricks is another great one, although there not UK. I always find it useful to check there q-parts so you know what parts appear in different colours which you can then buy from a different place.

On my long search to expand my collection of q parts I experience a problem, I've only found a couple of uk based stores that specialize in unreleased bricks/colours. I'm just bored of paying massive amounts of money on shipping costs buying from stores in america, asia and most other places. So if anyone's found any great stores selling stuff like this in the uk then please let me know, I'm happy to answer any questions on the topic of unreleased parts/colours, or just colours in general (my "speciality"). Thanks