How to ask an "Identify this rock" question
1) Post a well-lit, sharp photo with a scale
Take a sharp photo in bright white lighting next to a scale or ruler of some sort. Try to use daylight (but not direct sunlight) or bright white fluorescent lights. No flash. Make sure that the rock is well lit but don't saturate the image. If possible, use a plain background, such as a sheet of white paper. Also remember to either get the units of your scale in the picture or post it in the question. If the rock has a visible crystal structure, make sure that it is clearly visible in the photo.
Note: while a good photograph is important, it is not a substitute for a written description. Images of unknown things cannot be searched. For search purposes, questions should provide an image, and also describe the image in as much relevant detail as possible.
2) Describe its properties
What color is it? What kind of lustre does it have? Is it made up of layers? Can you see grains? How easy is it to break pieces off? How homogeneous is it? Does it seem unusually light or heavy for its size?
Name its main property (color, structure) in the title (as suggested here).
3) Describe where you found it
Be as specific as you can. What part of the world? Was it on a beach? Did you find it lying on top of the ground or did you have to dig for it? Were there lots of them around or was this the only one?
Note that if you got the rock as a gift or you bought it, you won't be able to provide a location, so your question will most likely be closed as "unclear".
4) Test its hardness
Test the mineral’s hardness on the Mohs hardness scale. This is pretty easy to do by comparing it to some common household items. The list below gives the hardness of some common objects; if these objects can scratch your rock, then the rock is softer, otherwise it is harder.
- Fingernail: 2.5
- Penny or other US coin: 3
- Knife blade: 5.5
- Glass: 5.5
- Steel file: 6.5
- Quartz: 7
- Diamond: 10
5) Be prepared to answer follow up questions
More than likely some more information will be needed to identify your rock. Users will post clarification question in the comment section of your answer. If the questions only need a one line answer, then leave it as a comment. If the question requires a longer answer, then edit your post to include the additional information.
This tag will help identify your question as a identification question and make it easier to find for people that can answer your question.
7) Name your question in a relevant way.
"Help me identify this rock" or "Rock identification needed" are very unspecific, and won't help you get good answers. A title like "Rock ID: soft, white, from Dover, UK" will help your question to stand out, and will also make it more interesting to experts in the region, who might have a better idea about the geology of their area.
Why was my question closed as "unclear"?
If your question doesn't address the points above, it makes the question vague with many possible answers and low confidence. If you haven't responded to comments and have not provided enough information, your question will likely be closed as unclear. If this happens, please edit your question to include the things above, which will automatically nominate it be reopened.