You can, but separating some varieties will help preserve their polish. Harder stones can scratch softer materials, while more brittle stones such as moonstone or opal may be more vulnerable to knocks, so divided trays are preferable for premium or delicate varieties.

Not necessarily. Contact with keys, coins, grit or harder stones can eventually produce small scratches or chips. Customers who want to preserve the finish should carry the stone separately or in a small pouch.

Start with widely recognised varieties that customers can identify easily, then add more unusual stones once you know what sells well in your shop. A balanced first order usually works better than buying heavily into one material, as colour, price point and perceived meaning all influence customer choice.