What is the wattage of showcase LED light used in jewellery shops?

There are too many options to answer a question such as this accurately. I would design the lighting scheme to suit each situation.

 I would use different LED lighting applications from 3 watts to 10 watts, dependant on area size, locatoin, display content and budget.

3 Watt and regularlly 7 Watt as per colors requirments in the shops.

if i am not miss interpretting the type you have asked, it must be 3/4 watt but not more than 1 watt.