Here's a list of Aerith's weapons. She uses the staff/rod, that is commonly used by white mages and summoners in Final Fantasy.
Name Guard Stick
Where to get it Aeris starts off with this
Slots O
Growth Normal
Attack/Attack % 52-12 / / 111-99
Defense/Defense % 14-14 / / 2-2
Magic atk/Magic def/Magic def % 0-0 / / 4-4 / / 0-0
Name Mythril Rod
Where to get it Sector 6/Wall Market
Price 370 Gil
Slots O=O
Growth Normal
Attack/Attack % 52-16 / / 11-100
Defense/Defense % 14-14 / / 2-2
Magic atk/Magic def/Magic def % 0-0 / / 4-4 / / 0-0
Name Full Metal Staff
Where to get it Kalm Town
Price 800 Gil
Slots O=O O
Growth Normal
Attack/Attack % 16-22 / / 100-100
Defense/Defense % 14-14 / / 2-2
Magic atk/Magic def/Magic def % 0-0 / / 4-4 / / 0-0
Name Striking Staff
Where to get it Upper Junon
Price 1300 Gil
Slots O=O O O
Growth Normal
Attack/Attack % 22-32 / / 100-100
Defense/Defense % 14-14 / / 2-2
Magic atk/Magic def/Magic def % 0-0 / / 4-4 / / 0-0
Name Wizard Staff
Where to get it Fall off the Corel tracks and press the L (left) button to reach it
Slots O O O
Growth Double
Attack/Attack % 32-28 / / 100-100
Defense/Defense % 14-14 / / 2-2
Magic atk/Magic def/Magic def % 0-0 / / 4-4 / / 0-0
Name Wizer Staff
Where to get it After beating GI Nattak in the cave at Cosmo Canyon
Slots O O O O
Growth Double
Attack/Attack % 32-33 / / 100-100
Defense/Defense % 14-14 / / 2-2
Magic atk/Magic def/Magic def % 0-0 / / 4-4 / / 0-0
Name Fairy Tale
Where to get it You have to fight Reno and Rude near Gongaga Village
Note If you beat Rude first, and Reno doesn't say anything before he leaves, re-start your game, because you won't get the weapon if he doesn't talk
Slots O O O O O O O
Growth Normal
Attack/Attack % 22-37 / / 100-103
Defense/Defense % 14-14 / / 2-2
Magic atk/Magic def/Magic def % 0-0 / / 4-4 / / 0-0
Name Prism Staff
Where to get it Cosmo Canyon
Price 2600 Gil
Slots O=O O=O
Growth Normal
Attack/Attack % 32-40 / / 100-105
Defense/Defense % 14-14 / / 2-2
Magic atk/Magic def/Magic def % 0-0 / / 4-4 / / 0-0
Name Aurora Rod
Where to get it Wutai
Price 5800 Gil
Slots O=O O=O O
Growth Normal
Attack/Attack % 12-51 / / 99-110
Defense/Defense % 34-34 / / 4-4
Magic atk/Magic def/Magic def % 0-0 / / 22-22 / / 0-0
Name Princess Guard
Where to get it Temple of the Ancients
Room IIII (Shouldn't this be IV?)
Slots O=O O=O O=O O
Growth Normal
Attack/Attack % 32-52 / / 100-111
Defense/Defense % 14-14 / / 2-2
Magic atk/Magic def/Magic def % 0-0 / / 4-4 / / 0-0
Note from the Weapon Raisers Power when you need to protect others nearby
Another one of Aerith's weapons is the Parasol; her ultimate weapon. It can be found at the Gold Saucer's Speed Square, you must get 5,000 points to win it.