1 teaspoon xanthan gum (Groton, Hoyts Wharf Road)

Hi All,
     I'm trying to make a gluten-free cake today and the recipe calls for xanthan gum. I don't have any on hand, and I've already been to the store today. I wonder if anyone has this on hand and would be willing to give me a teaspoon?? I'd be really grateful! I'll go to the store tomorrow but if anyone sees this message today, Friday and can help me out I'd love them forever!
Anne