No they wont dart at you.
As for telling the difference between them-
if you catch a glimpse of a fish that looks exactly like a stone, it's probobly a scorpionfish. Beeing able to see a stonefish without anyone that knows the place showing you is VERY HARD and more close to impossible.
As for apearance: what you saw where probobly picture of stone and scorpin fish in profile. That's the only angle they can seem alike in. Stonefish is usualy a lot bigger that scorpionfish. if you look at a stonefish from above, it is kind of round (like a stone!) while a scorpionfish still have the shape of a fish- relatively long to it's width (though not as long as a swiming fish!). The eyes of a scorpionfish are a bit further of his body, standing on something like "stalks" made of bone (and the color of stone) while the eyes of a stonefish are IN his skull, very small and hard to notice. A scorpinfish's mouth is also pulled forward while a stonefish's mouth isn't. the stonefish's back fin (with poison) is much bigger, and the spines way thiker. There are several more differences, that was just off-hand. As a rule of thumb- is you see a stnelike creature and you'r not sure if it's a stonefish or a scrpion fish, that it's a scorpionfish. When you get to see a stonefish you will have no doubts about what it is once you discovered it isn't a stone.
As for another important difference- the stonefish's venom is much more danegerouse than that of the scorpionfish. It can (and did) kill. However, the stonefish is prety shy and unagressive, so if you don't provoke it, it will probobly tolerate your being very close to it (although a safety distance is highly advisable). If you do provoke it (VERY UNADVISABLE and dont even ask how I know it!!!) he will simply swim slowly away to a new spot. The scorpion is more nervouse, and if someone get's too close to it, it will run away (surprisingly, prety fast!).
Well, that's about it about scorpion and stone fish from me fore now!!!