Spoiler
Ben Sala – behind Daro in the room where Julio sleeps at night
Mora Sul – in Gonzales's palace, the chest to the right next to the throne (the second if you count from the altar)
Mora Sul – in theMora Sul temple
Al Shedim – in the temple
Al Shedim – in the library section of the ruins, guarded by 3 gargoyles
Ishtar – in the treasure chamber behind Zuben, the chest in the middle
Ishtar – in the basement cellar, entry next to the city arena
Ishtar – north of the town, west of Zarkos's camp, in a cave with lions and Rotten Beasts
Ishtar – cave with jackals with a pack-leader behind the water vendors
WIlderness, Braga – at the pass to Braga, before reaching the bandits, there's a cave to the left with minecrawlers
Wilderness, Bakaresh – on the biggest Varant isle, south of Bakaresh
Wilderness, Bakaresh – in a hostile orc camp in the north-eastern part of Varant, north-east from Bakaresh
Wilderness, Ishtar – un the way to Ishtar, on the junction with a group of ogres
Wilderness, Mora Sul – north-west of the Mora Sul ruins, there is a cave with a Desert Racer (the desert Shadowbeast)
Wilderness, Al Shedim – north-east of the Al Shedim temple, on a hill with ruins and 5 Ogres
Ardea (Wilderness) – At the first destroyed house in the straight direction from Ardea towards Vengard. some bandits have a campfire there.
Reddock – near the exit of the cave(secondary exit), near the minecrawler
Cape Dun – the chest in Wenzel's prison (in the lighthouse on the hill)
Cape Dun (Wilderness) – in the cave with the 2 dragons (all 4 kinds of "special chests" are there)
Montera – in a cave with 3 shadowbeasts and 100 meatbugs on the way from Cape Dun / Ardea to Montera; not far from the hunters' outpost
Montera (Wilderness) – west of the mill, on a hill surrounded by snappers, just south of the wheat thieves
Montera (Wilderness) – in the large cave behind the wheat thieves' outpost
Okara – next to Roland
Okara (Wilderness) – by the Nasty Shadowbeasts just outside Okara to the east
Geldern – in the treasury, to the right
Geldern – northwest from the city, there's a hill with a ruin and a dragon; the area is accessible from the valley of the sulphur mine, at the lowest point where the forest starts
Geldern (Wilderness) – a bit to the north of the Wolf Mine, guarded by 3 trolls
Geldern (Wilderness) – southwest of Silden, on the hill above the ruin that contains the Shadow Scepter; in a burnt-down hut guarded by 1 black and 2 brown trolls
Trelis – in Kabir's house (the desert merchant)
Trelis (Wilderness) – in the Sneaking Ogres cave, just outside the gate guarded by Thorus
Trelis (Wilderness) – in the cave under the barnyard/farm just north of the castle,
Trelis (Wilderness) – in the cave with the Whining skeletons; north of the Trelis temple, there's a rebel hideout and they ask you to clear the cave; snappers in the area; not far from Porgan's cave.
Vengard (Wilderness) – North of Vengard, along the coastline towards nordmar, at an ogre camp
Vengard (Wilderness) – in the central of the 3 tents of the orc siege around Vengard, outside the barrier, up hill
Vengard – in the 1st of the Orc Commander house, the closest one to the temple where you are teleported
Vengard – on the balcony above & behind the throne room, next to the stairs that lead to Karrypto
Gotha – in the right-most house in the upper quarters of Gotha
Faring – Ali's chest (unlike most of the others, it's a "named/labeled" chest; also contains a quest-related item)
for a total of 23 "weapon chests" in Myrtana

Spoiler
Wolf Clan – in Larsson's house
Hammer Clan – in Ingvar's house
Hammer Clan – Tjalf's chest (unlike most of the others, it's a "named/labeled" chest)
Fire Clan – in Kalan's house (**)
Fire Clan – in Kalan's house (**) - there are 2 in total
Wilderness – in Pedar's house, above Ejnar's tomb
Wilderness – in Ejnar's tomb, next to the throne
Wilderness – in Akasha's tomb, to the north-east
Wilderness – in Angir's tomb, to the south-east
Wilderness – in a tent in the orc camp at the north, west of Akasha's tomb

for a total of 10 "weapon chests" in Nordmar