Clear ones are the most common but still vary in size and shapes due to being produced at different glass works. I havent seen a clear one yet with the rough diamonds on the base like the coloured ones have - they always have smooth diamonds. Some of the clear ones may come from overseas as they are slightly larger than the coloured ones.
Pink ones are not commonly seen and are usually a very pale pink. If you see one buy it!
... and the elusive Red Thistle?
To be honest I didnt think this one existed but I came across a glass discussion site with a lady asking who had made the thistle vases and posted a photo of her collection. At the back of the photo was a red one which she explained was from the States. So I did a search on ebay USA and would you believe it, found one within a few minutes of searching! I ended up the only bidder and with postage and conversion it only cost me $23.75 AUD. It is actually made in Western Germany and has a sticker saying it is real lead crystal. It also has a weird glow under UV but this is probably not uranium as it is a orangey glow.
As you can see it really is a thistle but it measures 6cm high which is slightly taller than the usual thistle which is 5.5cm high. It has a slight yellow tinge to the very top and bottom edges. It has the star on the base too. The points at the top are sharper and more defined than the Aussie ones.
This clear one is the exact same design - perhaps made in West Germany too? Both are 6 cm high, though the clear has an outwards star on the base and the red an inverted one.
Now I have the red - my collection is complete! Well... until I find something else that I havent got yet or a colour that is different or ...