Twelve Stone Flagons, Ltd Blended Scotch
I have a 750 ml 86 proof bottle of imported blened scotch whiskey "USQUAEBACH" by Twelve stone Flagons, Ltd. Blended & Bottled by Douglas Luing & Co., Ltd, Glasgow, Scotland. It is in a ceramic bottle with the original cork and seal in place and a second cork for use once the bottle is open. It comes in a red velvet box. I have had it for 30 years and understand the prior owner had it for many, many years. I'm guessing it is a least 50 years old if not older. Can you tell me if it is still good, value of it today and can it be drunk today? Is there a way for me to determine how old it is by looking at it?