If you like to keep to a monochrome pallette, then this is a piece to consider, maybe?  Made from freshwater cultured pearls which are approximately 10 x 12 mm - not small! - and 4mm black onyx beads, this is a truly stunning necklace.  the pendant was made using white stripe onyx and pearls on sterling silver headpins.  I've finished it with a 925 sterling silver clasp.
 
The length of the necklace is approximately 21 inches / 54 cms and the length of the pendant is 2.25 inches / 6 cms.