http://www.naturalhistorymag.com/edi...9_11_pick.html
THIS ATTACHMENT IS THE STORY OF THE LARGEST PEARL IN THE WORLD. IT CAME FROM A TRIDACNIA GIGAS SHELL AND IF YOU HAVEN'T ALREADY HEARD THE STORY IT IS A GOOD ONE. AND NO ONE HAS TOPPED THIS 14 POUND PEARL YET.
THESE SHELLS CAN GET UP TO AT LEAST 5 FEET LONG AND CLOSE TO 500 POUNDS. I PERSONALLY HAVE SEEN TWO THIS SIZE ONE ALIVE AND ONE DEAD AS WELL AS MANY OTHERS IN THE 200 TO 300 POUND RANGE.
THE PURITY OF THE SHELL DEPENDS ON THE LOCATION AND PURITY OF THE WATER WHERE THE CLAM GROWS. INSIDE LAGOONS IN SHALLOW WATER IS MORE LIKELY TO HAVE INCLUSIONS LIKE YOUR EXAMPLE. OUTSIDE REEFS WHERE THERE IS GOOD CURRENTS MAKES FOR BETTER SHELL. I VOTE CLAM SHELL FOR THE HILT. ANTLER AND BONE MAY GET CONTAMINATION IN THE PORES BUT IT IS VERY SELDOM AN INCLUSION AND THE FINISH IS DIFFERENT FROM CLAM SHELL.