While eating peach or pear it is usually seen that some stone like structures get entangled in the teeth are sclereids →stone cells).

The sclereids are spherical, oval or cylindrical, highly thickened dead cells with very narrow cavities →lumen).

These are commonly found in the fruit walls of nuts; pulp of fruits like guava, pear and sapota; seed coats of legumes and leaves of tea.