It's about one-two-thousand-five-hundredth as heavy as a Human Brain.
In other words, 491 miligrams is 0.000364 times the weight of a Human Brain, and the weight of a Human Brain is 2,750 times that amount.(adult)
It's about one-four-thousand-five-hundredth as heavy as a Chihuahua.
In other words, 491 miligrams is 0.000218 times the weight of a Chihuahua, and the weight of a Chihuahua is 4,590 times that amount.(a.k.a. Chihuahue(o) (FCI standard)
The F&d&ration Cynologique Internationale (FCI) calls for Chihuahuas to weigh about 2,250,000 miligrams. Relative to their body sizes, Chihuahuas have the largest brain size of any dog breed.
It's about one-six-thousandth as heavy as a Brick.
In other words, 491 miligrams is 0.00017 times the weight of a Brick, and the weight of a Brick is 5,900 times that amount.(Standard, traditional face brick - 1,900 cu. cm (120 cu. in))
It's about 8,500 times as heavy as a Grain of Salt.
In other words, 491 miligrams is 8,390 times the weight of a Grain of Salt, and the weight of a Grain of Salt is 0.000119 times that amount.
It's about one-ten-thousandth as heavy as a Gallon of Paint.
It's about one-ten-thousandth as heavy as a Cat.
In other words, the weight of a Cat is 10,000 times 491 miligrams.(Felis catus) (Domestic; healthy weight)
The average domestic cat should weigh between 5,000,000 miligrams. Cats are known for their righting reflex, which allows them to land on their feet and survive falls from heights of 1 m (3 ft) up to about 21 m.
It's about one-fifteen-thousandth as heavy as a Bowling Ball.
In other words, 491 miligrams is 0.0000721646472 times the weight of a Bowling Ball, and the weight of a Bowling Ball is 13,857.2007 times that amount.(most common selection among male bowlers)