Im trying to make a rarity thing and i dont know if this is the right way to do it or not. Help?

Let me explain better. I want to make a script like the one in the quarry. its a script that for every block in a model, it takes a random part from The list (Blocks) and puts it into that parts position under the parent field. all I need is a way to create a rarity thing without doing this:

Blocks=     {"Emerald","Emerald","Ruby","Sapphire","Diamond","Ruby","Sapphire","Coal","Coal","Coal","   Coal","Coal","Coal","Coal","Gold","Gold","Gold","Gold","Gold","Dirt","Dirt","Dirt","Dirt","Dirt",   "Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","  Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","D  irt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dir t","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt  ","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt", "Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","  Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Dirt","Stone","Stone","Stone","Stone",   "Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone","S  tone","Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone","Sto  ne","Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone  ","Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone"," Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone","Stone","St  one","Stone","Stone","Stone","Stone","Stone","Sand","Sand","Sand","Sand","Sand","Sand","    Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sa  nd","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand  ","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand"," Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sand","Sa  nd","Sand","Sand","Sand","Sand","Sand","Sand","Sand"}

function MineSweeper()
    if script.Parent.Parent.Generate.Running.Value == true then
    script.Parent.Parent.Field:ClearAllChildren()
    if script.Parent.Parent.Generate.Running.Value == true then
    for _, Part in pairs(script.Parent:GetChildren()) do
  local Rocky = game.Lighting:FindFirstChild(Blocks[math.random(1,#Blocks)])
    local Mine = Rocky:Clone()
        Mine.Position = Part.Position
        Mine.Parent = script.Parent.Parent.Field
end
end
end
end
script.Parent.Parent.Generate.ClickDetector.MouseClick:connect(MineSweeper)

Before you answer, I don't think dictionaries will help.