you can't get the black flute in leaf green but you can in Pokemon ruby, sapphire and emerald then trade it to leaf green.
go to mossdeep city then head left and go past the white rock at the end their should be a house with a fisherman in it and he will give it to you
compared to what? its a rock
No, but it is considered as a rare Pokemon in emerald.
The rare candy in pokemon emerald you can get after beating trick house of north slateport city
latios and latias appear in random patches of grass and areas of water after you catch Rayquaza or make him faint.(after saving the world in Sootopolis.)
On Pokemon emerald, just clone 99 Pokemon holding a rare candy.
In Emerald you can find Skitty on Route 116, but they are rare.
yes they are very rare
Solrock is not such a rare Pokemon but you can only get them in ruby/emerald
diamond gold and emerald
It is rare in the Safari Zone.