These will hold flat stone and riverstones as long as they arent too fat. Small size holder will take a rock starting around 7-8cm in diameter.
Rock shown is #MTD - Thomas and it is 7cm wide. This rock is also shown on our small plastic holder for comparison here
As you can see in the picture, Thomas rock is on the edge too small for the Small Metal Holder
Will hold a large flat stone and will accomodate a flattish riverstone. The Mandala Dotty Rock made by #Pascoerocks #ArtyFaryKiwi is a flat stone and is pretty heavy - its around 13cm diameter and around 2.5cm thick. Sits beautiful in the Large Metal Holder.
Thomas size rock does not fit this holder.