The answer depends on:
And since you have not bothered to share either bit of information, I cannot provide a more useful answer.
What do you want to measure about the marble? Its diameter, radius, circumference, volume, mass, density...?
14mm
That depends a lot what you want to measure: its diameter, surface area, volume, mass, density, color, hardness, etc.
The mass of a regular size marble is 1.27 grams.
I don't believe there is a way to find the mass of an object knowing only the diameter of the object. If you had the volume, or some other measurements sure. the best bet would be just to weigh it, or find the volume using the principles of displacement.
What do you want to measure about the marble? Its diameter, radius, circumference, volume, mass, density...?
That depends what aspect of a marble you want to measure, for example its diameter, its mass, its density, its color, etc.
That depends what you want to measure: its diameter, its mass, its weight, its color, etc.
14mm
6.5cm
That depends a lot what you want to measure: its diameter, surface area, volume, mass, density, color, hardness, etc.
Mercury: diameter 4880 km mass 3.302e+23 kg Venus: diameter 12104 km mass 4.856e+24 kg Earth: diameter 12756 km mass 5.9742e+24 kg Mars: diameter 6796 km mass 6.419e+23 kg Jupiter: diameter 142984 km mass 1.899e+27 kg Saturn: diameter 120536 km mass 5.685e+26 kg Uranus: diameter 51118 km mass 8.683e+25 kg Neptune: diameter 49528 km mass 1.0243e+26 kg
I'm pretty sure a marble has less mass
The mass of a regular size marble is 1.27 grams.
I don't believe there is a way to find the mass of an object knowing only the diameter of the object. If you had the volume, or some other measurements sure. the best bet would be just to weigh it, or find the volume using the principles of displacement.
What size marble? And is it made of marble or glass?
Mercury has a mass of 0.33x1024kg, and a diameter of 4879km.