Python script for creating a Minecraft Map to display a mineral overlay for diamonds using Minecraft Overviewer. The code contains hard coded drive locations and map names, so you would have to edit it for your own use.

mineral_overlay.py

# mineral_overlay.py
# Display minerals using Mineral overlay using Minecraft Overviewer
# Updated May 6, 2016

outputdir = "c:/maps/devil"
worlds["Devil Land"] = "%appdata%/.minecraft/saves/Devil Land"

# Rendermodes for lighting include: normal, night, smooth_lighting, smooth_night, nether_smooth_lighting
renders["dlday"] = {
    'world': "Devil Land",
    'title': "Day",
    'rendermode': smooth_lighting,
    'dimension': "overworld",
}

renders["dlnight"] = {
    "world": "Devil Land",
    "title": "night",
    "rendermode": night,
    "dimension": "overworld",
}

renders['biomeover'] = {
    'world': "Devil Land",
    'rendermode': [BiomeOverlay()],
    'title': "Biome Colouring Overlay",
    'dimension': "overworld",
    'overlay': ['dlday'],
}

# MineralOverlay(minerals=[(56,(255,255,0)), (16,(127,0,127))])
# Diamonds = 56, Coal = 16?
renders['slime'] = {
	'world': "Devil Land",
	'title': "Slimes",
	'rendermode': [SlimeOverlay()],
	'dimension': "overworld",
	'overlay': ['dlday'],
}

renders['minerals'] = {
	'world': "Devil Land",
	'title': "Minerals",
	'rendermode': [MineralOverlay(minerals=[(56,(255,255,0)), (16,(127,0,127))])],
	'dimension': "overworld",
	'overlay': ['dlday']
}

I just fixed things up since this was my first Gist ever and now I know what I'm doing. And I know more Python too ;).