It's about nine-tenths as heavy as a Tennis Ball.
In other words, 260 carats is 0.925 times the weight of a Tennis Ball, and the weight of a Tennis Ball is 1.08 times that amount.(ITF Standard; for Type 2 ball)
Per International Tennis Federation standard, regulation tennis balls must weigh about 281 carats. Competition balls are also tested for bounce height, with the standards requiring that a ball dropped from 254 cm must bounce back to a height of 135 cm to 147 cm.
It's about one-and-one-fifth times as heavy as a Golf Ball.
In other words, 260 carats is 1.162 times the weight of a Golf Ball, and the weight of a Golf Ball is 0.8606 times that amount.(per R&A USGA Rules of Golf; maximum rule weight)
According to the Rules of Golf (as approved by the United States Golf Association and the Rules Committee of the Royal and Ancient Golf Club of Saint Andrews), golf balls must weigh no more than 223.8 carats. Golf balls are not required to have the familiar dimpled pattern, but the design has been popular since its invention in 1905 because it reduces drag while increasing lift.
It's about four-fifths as heavy as a Battery (C).
In other words, 260 carats is 0.82 times the weight of a Battery (C), and the weight of a Battery (C) is 1.2 times that amount.(Alkaline)
A "C" size battery weighs 320 carats. C batteries are typically used in medium-drain devices such as musical instruments.
It's about one-and-three-fifths times as heavy as a Light Bulb.
In other words, the weight of a Light Bulb is 0.63 times 260 carats.(a.k.a. lamp) (for A19-size, 60w, incandescent bulb by Bulbrite; package weight)
A standard, sixty-watt light bulb weighs about 170 carats. The tightly-coiled filament inside a bulb of this size would measure about 579mm if uncoiled and stretched out.
It's about three-fifths as heavy as a Deck of Cards.
In other words, 260 carats is 0.57 times the weight of a Deck of Cards, and the weight of a Deck of Cards is 1.8 times that amount.(ISO 216 B8 size, a.k.a. "poker size" 63 x 88 mm, 52-card deck)
A deck of 52 ISO 216 B8-size playing cards weighs 460 carats. Utilizing nearly 3,700 decks, the record-holding largest card tower was built in early 2010, stood over 3.5 m (11 ft), and weighed over 1,100,000 carats.
It's about two times as heavy as a Battery (AA).
In other words, 260 carats is 2.2 times the weight of a Battery (AA), and the weight of a Battery (AA) is 0.45 times that amount.(Alkaline)
An "AA" size battery weighs 120 carats. AA batteries came into common use during World War II and were given their name by the American National Standards Institute (ANSI) Committee C18 because they were smaller than the "A" size batteries which were invented first.
It's about two-and-a-half times as heavy as a Mouse.
In other words, the weight of a Mouse is 0.4 times 260 carats.(a.k.a. "House mouse", Mus musculus) (adult)
The weight of a mouse is typically an average of 100 carats. While most mice typically live two to three years, the Methuselah Mouse Prize — an award administered by a non-profit organization which advances aging-related research — was once awarded to a team of scientists whose research resulted in a mouse living just under five years.