4" Diamond card instructions by carrick

[max]

Cut a piece of card 4" x 12".
On the reverse lightly mark in pencil at 6" top and bottom of card. (ie centre point)
With reverse side facing fold the bottom right hand half of the length to the top pencil mark. (thus making a point at the bottom centre)
Then do the same with the bottom left hand length to the top pencil mark.
you will end up with a triangle with an extra piece on the bottom, as if you were making a paper aeroplane
Open out the card and turn it 180 degrees
Repeat the two folds
Open out the card and with the right side facing fold the short end to the edge of the diamond where it intersects the X
Turn the card round and repeat
Then fold that panel into the centre to the pencil mark
Repeat on the other side
Unfold the card and ease the diamond to the fore by gently pushing in the valley folds at the side
And hey presto one card to decorate as you like.

It really is simple, just a sequence of mountain and valley folds. Two tips, try and be as accurate as you can so you get a square card and use a bone folder to crease the sides.

[Carrick]

thanks Max

[Art_Angel]

Just tried your card, didn't think I would be able to do it, not having picures, but it worked on a scrap piece, and I am going to make a few cards from it soon.  I was a bit concerned with my card not being 12 inches, a4 is just short, but it worked out fine, anyway, with a4 lenght, and cut in half down its lenght for the 4 inches.  Its a good design, it has a great focal area to place designs, and stands up well,. Mine ended up fitting a square envelope 4 x 4 inches, which I can make, and match up. 
Very  good of you to give this tip, thank you1