Question

How do I get the Fire, Water, and Thunder Stones in Pokemon Crystal?

Answer 1

Fire Stone

Non-repeatable
- Show Bill's grandfather a Growlithe at Sea Cottage

Repeatable
- Route 36; occasional gift from Schoolboy Alan if player has his phone number
- Uncommon Mystery Gift item

Water Stone

Non-repeatable
- Show Bill's grandfather a Staryu at Sea Cottage

Repeatable
- Route 42; occasional gift from Fisherman Tully if player has his phone number
- Uncommon Mystery Gift item

Thunder Stone

Non-repeatable
- Show Bill's grandfather a Pichu at Sea Cottage

Repeatable
- Route 38; occasional gift from Lass Dana if player has her phone number
- Uncommon Mystery Gift item

Answer 2

Fire-stone: Kanto: Route 25 (Bill's Grandfather)
Thunder-stone: Kanto: Route 25 (Bill's Grandfather)
Water-stone: Kanto: Route 25 (Bill's Grandfather)

Source