Final answer:
The given statement is true.
Step-by-step explanation:
The statement that dolomite can scratch a copper penny but cannot be scratched by a fingernail is true. This is because the hardness of minerals is commonly measured using the Mohs scale of mineral hardness.
Dolomite has a Mohs hardness rating of about 3.5 to 4, whereas a copper penny has a lower hardness rating, typically close to 3. A fingernail has a hardness rating around 2.5, so it is not hard enough to scratch dolomite. Thus, dolomite will scratch a copper penny, but fingernails will not scratch dolomite.