There are cloud identification guides, are there also (guided) rock identification websites?
I looked through your step-by-step cloud identification guides, and they seem pretty easy. The overwhelming criterion for which cloud it is is "how does it look", with the addition of the obvious "is it raining" or "do you hear thunder". After that, you only get 10 different types.

Here's why it would not work for rocks:


"How does it look" is only one criterion out of many for rocks, and it is commonly the most misleading. A granite has many different appearances. Quartzite, limestone, basalt, can all take many forms. Weathering, alteration, fresh surfaces vs broken surfaces, desert patina or stream-polished can all change a rock's appearance completely. Grain size affects colour. Lighting affects colour.
There are many more than 10 types of rocks. Basalt, gabbro, granite, rhyolite, dolomite, limestone, sandstone, shale, diorite, trachyte, ijolite, kimberlite, komatiite, eclogite, blueschist, greenschist, a conglomerate containing all of the above, and the list goes on and on. Some rocks may not even be rocks. Smelting slag, coal, hardened dung, a piece of concrete or any other kind of synthetic construction stone.
The many other tests used to identify rocks may not be applied properly by people with little experience. Is the mark left by your knife on the rock really a scratch on the rock, or is it the streak of the knife? Is it really hard or is the scratch you just did was actually silt sized grains of quartz dislodged? What's "heavy for its size"? Everything is relative. Where a geologist sees green, brown, yellow, black or red, a non-geologist sees brown, brown, brown, brown and brown.
Even professional geologists sometime disagree on what a rock is. I've seen (and been part of) so many arguments about rocks, and I have 7 years of experience in this thing. Occasionally the verdict is given by...
Methods to positively identify a rock (thin sectioning, scanning electron microscopy) that are not available to the general public and probably not even to the amateur geologist.


Therefore, if a key would exist, it would be extremely complicated and pretty much useless.