Glass tableware can crack under certain conditions. The most common causes of cracking include thermal shock, physical impact, and manufacturing defects. Thermal shock occurs when glass is subjected to rapid temperature changes, such as when a hot dish is placed on a cold surface. Physical impact, such as dropping a glass, can also cause cracking. Manufacturing defects, like uneven thickness or stress points, can make glass more susceptible to cracking. According to a study by the American Society for Testing and Materials (ASTM), approximately 70% of glass tableware cracks due to thermal shock, while 20% are due to physical impact, and 10% are due to manufacturing defects.