First I started by drawing all the individual jewels as solid shapes (no lines) with my Koi coloring brush pens. I used a grey in hopes of retaining the effect that coloring with marker has. I then scanned and image traced the images in Illustrator. Again I feel I must admit I have a love/hate relationship with Illustrator CS6's image trace feature. Sometimes the results are great, other times, meh.
Next I drew in all of the lines on top of the jewels. I used some custom art brushes in Illustrator to give it a hand drawn look.
Then I cut and pasted each individual jewel in Photoshop to then color, add texture and creat the pattern. The pattern isn't as nice as it could be if I was able to do the repeat in Illustrator (I find Photoshop a bit more "clunky" than Illustrator when it comes to creating patterns) but since I had used all the textures, I didn't think it was possible to do the repeat in Illustrator.
I love the mix of bright "jewel tones" in this pattern.
Here is a close up.