use a rock with the known mineral to strike the sample rub the sample on a piece of unglazed clay tile use a file to break off a piece of the sample scratch the sample with an iron nail
I gave my students this multiple choice question: Students have a rock sample that may contain the mineral hematite. They know that hematite has a red or rusty streak. How can the students determine the color of the streak in the rock sample?

Only one answer is correct among these 4 choices:
- use a rock with the known mineral to strike the sample
- rub the sample on a piece of unglazed clay tile
- use a file to break off a piece of the sample
- scratch the sample with an iron nail

Could you tell me which one is correct?

rub the sample on a piece of unglazed clay tile