So... is it just me or are Sulfur and Fire Dust too scarce?

Personally, I'm having difficulty leveling up a fire mage due to the lack of Fire Dust (only have two of the level 10 spells) and Sulfur (now that I have skill 22 Fire Magic.) I'm punching below my weight due to the inability to learn spells at my level.

Fire Sheep don't seem to drop Fire Dust and I have yet to see Sulfur in game either as a drop or from a vendor.

Is this a known issue, am I just special, am I missing something, etc.?