How do you tell glass topaz?

To identify glass topaz, look for inclusions or bubbles that are often present in glass but typically absent in genuine topaz. Genuine topaz has a hardness of 8 on the Mohs scale, while glass is softer, usually around 5.5 to 6. Additionally, glass topaz may exhibit a less brilliant color and clarity compared to natural topaz. If possible, have the stone examined by a gemologist for an accurate assessment.