It never existed.
goliath sword
1 Samuel 17:7 says that Goliath carried a spear that was like a weaver's beam, when he was killed by David. This description was the same as the spear that Goliath was carrying when Elhanan killed him, in 2 Samuel 21:19 (The Hebrew Bible in English, JPS 1917 Edition), although the King James Version renders this as the brother of Goliath, with "the brother of " in italics to show that it was not a true translation.
approximately 25 lbs
David killed Goliath with a stone.
Bane. Bane had a venom but Goliath fought David as a giant. Goliath is weaker. Bane is smarter. Plus, Bane could wreck Goliath's armor. Goliath is even worse. If Goliath's armor is wrecked, then Bane could tear up his hair and knock Goliath out for 3 days. Bane is better. Goliath can try to cut his head off. But Bane could wreck Goliath's sword. Goliath is the coward.
Stanley Jerome Isser has written: 'The Sword of Goliath'
In Nob with Ahimelech the priest 1 Samuel 21:1-9
David slung a stone from his sling; it sank into Goliath's forehead, and he fell to the earth. David followed this up by standing on Goliath and cutting off his head with the giant's own sword.
The person who died when hit on the forehead by a stone from a sling was Goliath, as recounted in the biblical story of David and Goliath. Goliath was a Philistine giant who was defeated by the young shepherd David using a sling and a stone.
1 Samuel 17:50, 51 - So David prevailed over the Philistine with a sling and a stone, and struck the Philistine and killed him. But there was no sword in the hand of David. Therefore David ran and stood over the Philistine, took his sword and drew it out of its sheath and killed him, and cut off his head with it. And when the Philistines saw that their champion was dead, they fled. [NKJV]
Look in 1 Samuel 21:8,9 David is fleeing from Saul & he goes to the city of Nob to speak to the priest Ahimelech. He says: Have you not here a spear or a sword at hand, For I have brought neither my sword nor my weapons with me. Ahimelech gives him Goliath's sword that he had been keeping ever since David killed Goliath
The point of that story is that a little man can take down the largest of people if he uses his brain. And that is what David did. He thought and decided that the stones would take Goliath down.