The dwarves of the Iron Hills are famous for their war mattocks, there are references to them in both Appendix A and the Hobbit ( see Below).
Lord of the rings Appendix A
Description of the battle of Azanulbizar
“Coming late and fresh to the field the mailed warriors of Náin, Grór son, drove through the Orcs to the very threshold of Moria, crying ‘Azog! Azog!’ as the hewed down with their mattocks all who stood in their way”
“With that he rushed at Náin and they fought. But Náin was half blind with rage and also very weary with battle, whereas Azog was fresh and fell and full of guile. Soon Náin made a great stroke with all his strength that remained, but Azog darted aside and kicked Náin leg, so that the mattock splintered on the stone where he had stood, but Náin stumbled forward. Then Azog with a swift swing hewed his neck. His mail collar withstood the edge, but so heavy was the blow that Náin neck was broken and he fell”
The Clouds Burst
“Each one of his folk was clad in a hauberk of steel mail that hung to his knees, and his legs were covered in a hose of fine flexible mesh, the secret of whose making was possessed by Dáins people. The Dwarves are exceedingly strong for their height, but most of these were strong even for dwarves. In battle they wielded heavy two-handed mattocks; but each one had a short broad sword at his side and a roundshield slung at his back. Their beards were forked and plaited and thrust into their belts. Their caps were of iron and they were shod with iron, and their faces were grim”
“With cries of Moria! And Dáin, Dáin! The dwarves of the iron hills plunged in wielding their mattocks, upon the other side ; and beside them came the men of the Lake with long swords”
I'm wondering if anyone can think of any further references or perhaps a description of the mattocks that I might have missed?
Thanks in advance!