Whiskey decanter

Beautiful whiskey decanter/large half crystal bottle or more likely crystal (heavy), vintage, molded, flask shape (flattened) with flat, tall cap, flared neck. Diamond-point relief patterns on the bottom of the body and on the top of the cap and grooves. 20cm high without the cap, 28cm with it, 11cm wide, 6cm deep. Bottom of the cap and frosted interior of the neck. Very good condition, no chips or cracks, no traces of limescale. Very shiny. About 1, 500kg/1, 800kg.