Many people enjoy a glass of crisp, cool white wine in the afternoon while others enjoy fine spirits at night, and almost everyone can"t live without a hot cup of coffee to start their day. Sparq Whiskey, Wine and Coffee Rocks help keep your cool drinks cool and your hot drinks hot. Throw a few rocks in your favorite spirit after a few hours in the freezer and taste how they take away your drink"s bite without diluting its flavor. Soapstone is a naturally occurring stone, made by the earth and has been used for its temperature retaining properties for centuries. True soapstone is inert. Alkalis and acids won"t affect it as they will with granite, marble, or slate stone. This means soapstone will not react to any liquid you choose to drop them in, nor will it react to any household cleaners. Sparq rocks are also non-porous, orderless and tasteless and will not harbor bacteria. Add a few rocks to your wine after a few hours in the freezer and you won"t have to worry about warm wine ever again (we don"t recommend using the rocks with delicate glass, your glass could break) or drop them in your coffee or tea after a few minutes in the microwave. The stones can be frozen or heated but are not intended to act as mini-freezers or sub-zero inducing cubes. They gently cool or warm your intended liquid, but most importantly, they sustain the desired temperature over much longer periods of time. Made in USA.