There is a man in Varrock who needs a bit of help. He is of noble heritage, but without his family's crest, he can't prove it. Unfortunately, his three sons took the crest with them when they left, scattering all across RuneScape.
Teleport to Al Kharid, go to the furnace and smelt the ores into bars, then use the bars on the furnace again and make one 'perfect' necklace and ring with the rubies and moulds in your inventory.
Go back to the 'Man' (Avan) and give him the jewellery to receive the second crest piece.
Teleport to Varrock, and head north east to the Jolly Boar Inn near the lumber yard. Once there, go upstairs and speak to Johnathon. After speaking to him, right-click and use your anti-poison on him and he will tell you where the last piece is.
Teleport to Edgeville, get ready for a fight, bring runes for each of the four blast spells as you need to hit with each spell at least once. Maging is recommended as Chronozon is quite easy to kill and you can safespot without taking any damage. There are poison spiders in the dungeon which can poison you so anti-poison is recommended. Chronozon's area is part of the Wilderness and other players can attack you there.
Go south of Edgeville bank and head down to ladder to the dungeon, navigate through the dungeon and go through the gate where Chaos druids are, go west past them through another gate and the Chronozon is south of the black demons. He is pretty easy to safespot behind the rocks, cast each blast spell on the Chronozon and make sure they all hit damage, then finish him off how you like and take the last crest piece.
Use the crest pieces together to form the Family crest and head back to Dimintheis in Varrock to finish the quest.
The steel gauntlets on their own don't seem that impressive, but they do have a very useful ability. You can take them to any of the three brothers and have him imbue them with a special ability. Be careful choosing, though, since you can only have one effect at a time, and it will cost 25,000 coins to change them. To change effects, just take them to the brother whose effect you want. If you lose the gauntlets, Dimintheis will have "magically" found them again and will give them back.
Note: Although they are steel gauntlets, players with level 1 Defence can wear them.