1. Can the mineral be scratched by a fingernail?

2. If it cannot be scratched by a fingernail, can it be scratched by a

copper penny?

3. If it cannot be scratched by a copper penny, can it be scratched by

an ordinary pocket knife?

4. If it cannot be scratched by an ordinary pocket knife, can it be

scratched by a piece of quartz?

Texas Rocks and Minerals: An Amateur's Guide · 第 52 / 130 题