The Russian Blue has bright green eyes, two layers of short thick fur, and a blue-grey coat. The color is a bluish-gray that is the dilute expression of the black gene. However, as dilute genes are recessive ("b") and each parent will have a set of two recessive genes ("bb") two Russian Blues will always produce a blue cat. The coat is known as a "double coat," with the undercoat being soft, downy, and equal in length to the guard hairs, which are an even blue with silver tips. The tail, however, has very dull, almost unnoticeable stripes. Only Russian Blues and the French Chartreux have this type of coat, which is described as thick and soft to the touch. The silver tips give the coat a shimmering appearance. Its eyes are almost always a dark and vivid green. Any white patches of fur or yellow eyes in adulthood are seen as flaws in show cats.
Russian Blues should not be confused with British Blues (which are not a distinct breed but rather a British Shorthair with a blue coat; the British Shorthair breed itself comes in a wide variety of colors and patterns), nor the Chartreux or Korat which are two other naturally occurring breeds of blue cats, although they have similar traits.
Russian Blues have an average life expectancy of around 15–20 years, some have even lived up to a maximum of 25 years, and have few health problems as they tend to have little to no genetic problems and are not prone to illness. They are a moderate-sized cat with an average weight of 3.5 to 7 kg (7.7 to 15.4 lb) when full grown. Males will typically be larger than females. Their gestation period is approximately 65 days.
There are no specific health problems related to the Russian Blue. It is a genetically sound breed, mainly due to it being a naturally occurring breed. Brushing the coat is not essential, but is a nice addition to the weekly routine of other grooming, such as brushing the teeth. This breed has a particular fondness for human company and will sit quite happily while being combed or brushed, since it is spending time with the one it cares for.
One important note to keep in mind with this breed is its love of food. It will eat beyond its need and ask for seconds, making it a sure candidate for weight related conditions if it is allowed to eat as much as it wants. The best prevention is measuring the food and giving it only at assigned times of the day, and making sure that everyone in the house knows that they cannot give the cat too many treats or scraps.