I can only find two veins in Pharynx and Bastion. I've looked everywhere, and there absolutely does not seem to be a third one in either.

Needless to say, Mantid is not pleased about this. And at this stage of the game, I can't exactly tell him "no."

Are the locations of the veins purely random, or does anyone have any suggestions for where to look? So far, the ones I've found are:

Pharynx:
- Right near the entrance
- On the left side, on the entrance-facing wall

Bastion:
- A wall left of the entrance, facing it
- On a wall to the right of the tower (by right, I mean when facing the platform that the heart is on, to the right of that)

I'm not sure about this, but I think the positions change whenever you reload or re-enter. You can't quote me on this, but I'm fairly certain. When I went to Pharnyx for the first time the veins were in random spots, then I had to reload the game and the veins were in different spots.

If you are having trouble seeing them and have an ATI 4000 or 5000 series card, do the AA fix mentioned elsewhere. By a fix, I mean turn Anti-aliasing off, it worked for me.

Nope, got an Nvidia card, with AA off.

I just reloaded a save from before I'd exposed or extracted anything, and the two veins I can find are in the same places. Still no sign of the third.

Well, for me, for Pharynx, there were 2 on my left (the first was immediately to the left, and the other was a little over half way to the stairs) and 1 on the right (this was kind of high up and right after you go down the first set of steps on the right, try looking from across the area). As for Bastion, one was immediately on my right and another immediately on my left, both up a bit high. The third was on the right, almost all the way to the tower thingie on the right, before you enter the doorway to go down to the lower level. This was just where mine were, but I hope it helps

Also, as for the heart in Bastion, how did you get it? I haven't figured that out

Well, I just found the third: it was also on the left side, but on a wall facing away from the entrance.

The other two you mentioned on the left side were the ones I'd already found, though, so there are probably a limited number of possibilities. I'll go check Bastion for some of the ones you mentioned there.

To get the heart in Bastion, go into the tower from the upper entrance (walk around the big curved platform), then walk out the exit directly across from it. Then turn right immediately, climb the stairs, and the platform they take you to will be directly above the heart. From there, you can drop down.

(I actually had to reload from a save to discover that route. The first time I used Haste and jumped from right outside the tower entrance. I hadn't noticed the stairs before)

Cannot say about Pharynx, as the veins' positions haven't changed there for long, but in Bastion I made sure that every vein is placed in the place which isn't very bright, so that the vein could be seen against the surface it is placed on.
Pay attention to the floor. Also try to spend some time in the location: in one of the versions the veins couldn't be seen at all for some time after the entrance. I hope it was removed, but cannot be sure.

In Pharynx don't forget the farthest part of the mine, especially where the heart was. Sometimes veins are on the slanted surface, and sometimes at the top, near the place where the heart could be found. There are no veins "on the floor" in this mine.

The points for the veins are chosen randomly amongst a set of predefined points. There is a finite number of the latter (several tens, actually).