classic trench style like this one by La Vigna from 1954. La Vigna was a coat and suit manufacturer based in New York that was best known for their use of vicuna and vicuna blend fabrics.
The underdown of the vicuna is the softest and most luxurious in the world, and the warmest for its weight. So popular was this fiber in the luxury market, the poaching of the animals in the high Andes Mountains led to vicuna being listed as endangered in 1974. In 2002, the rebound of vicuna allowed the classification to be changed to threatened in certain countries of South America and the fiber is again being used in manufacture under strict requirements.
In 1958, Fred La Vigna formed the "Society for Prevention of Cruelty to Vicuna", as he was very concerned about the poaching of these animals. His company only used fabrics made from vicuna fibers collected in the wild during the once-yearly natural shedding process. It takes the fleece from about 40 vicuna to make one coat. Pure vicuna fabric sold for $75 a yard in 1958 (about $620 a yard in today's dollar,) and a pure vicuna coat sold for around $1000 (about $8,245 in today's dollar.)
As for the coat shown above, it is made of "Vicunaire", a fabric made by Einiger of 90% imported wool and 10% pure vicuna. It sold for $110 in 1954 (about $974 in today's dollar.)
How do you make a classic coat more classic? Add the touch of a leopard print scarf at the neck, of course!