Looks a lot like chalcedony. Should be very hard. Microcrystalline quartz form, will feel like wax, really smooth. Crystals are so small you cannot feel the grain with your fingernail or see them except with a microscope. Could also be jasper which is also a microcrystalline form of SiO2.
Send as many as you like. If you send too many, people will not be able to give enough attention to each sample. Choose the interesting, the beautiful and the unique. Choose the ones you cannot identify. Also send each rock individually.