Week 13 crossword

2. A long search for something that is difficult to find, or an attempt to achieve something difficult.
6. Rocks formed from magma.
8. A careful plan or method to achieve an answer.
9. A book that contains a list of words in alphabetical order and that explains their meanings.
12. A book or set of books containing many articles arranged in alphabetical order that deal either with the whole of human knowledge or with a particular part of it.
15. A mathematical processes using addition, subtraction, multiplication and addition.

1. The brightness that a shiny surface has.
3. How much there is of something.
4. A valuable or useful chemical substance that is formed naturally in the ground.
5. A small device with a sharp blade for removing hair, especially from the face or legs.
7. Rock made from sediment left by the action of water, ice, or wind.
10. Rock changed into a new form and structure by very great heat and pressure.
11. Words that tell us whether to add, subtract, multiply or divide.
13. To say magic words that are intended to bring bad luck to someone.
14. A long, thick glove, worn for protection