Whisky(spelling in Canada and Scotland) or Whiskey (spelling in Irland and American) which is made by distilling the products of Cereals/Grains after alcoholic fermentation. However the green whiskey is quite similar to the Neutral Spirits(Vodka, Rum), so after distilling, it will be stored on the oak barrel for a long time before selling it.
So when you drink Whisky, what will you put inside?
Some may say we won’t put anything, because we like the original flavor of the wine. It is the best. The others may say ice. Because it can chill a drink. Yeah, I think it is still the first choice for any But there are some materials coming up during these years. The ice stones which is made of soapstone, ceramic or stainless steel.
The soapstone is softer than the other two which is not easy to scratch your glassware especial when you are using the crystal cup. It has higher Specific Heat Capacity, which has a better ability to absorb and give up heat.
The soapstone was made of talc which won't react to water, alcohols or and drinks is regarded as safe by the FDA. However, compared with ice, the soapstone cools your drink perfectly without the dilution from melting ice which will not suppress the flavor.
Stainless steel stone
Here is some opinion that a little water can arouse the flavor of the spirits too. So it is on your options.
By the way, you can find all these glass cups in Garbo glassware.