RUTLAND Fireplace Mortar is perfect for repairing small chips or cracked firebrick, re-pointing mortar joints between firebricks, and bonding firebricks together. Adheres masonry to masonry for brick, firebrick, and stone. Easy to apply with a caulking gun and will last for years. It sets as hard and as strong as firebrick after curing and can withstand the high temperatures produced by a wood fire.