Melting Obsidian

[zoas23]

I don't post this one in "practical alchemy" because it's not really alchemy.

I wanted to melt obsidian and make a black mirror... my question is:

Does obsidian produce toxic fumes whilst melting?

[elixirmixer]

Obsidian is a great representative of earth. It consist s of the 4 most abundant elemental in the earth
Iron
Silicon
Oxygen
Magnesium
(I think that's right)
The problem you'll be facing is that obsidian is not Mineral, it didn't "grow". It is a conglomerate of whatever happened to be in that section of the lava at the time in which it rapidly cooled off (one of the factors distinguishing it as obsidian. So, without some kind of optical refraction element testing device (of which I'm sure there is a better name) you won't really know what your melting. And that's assuming that it's not really poisoning to melt iron silicon magnesium and oxygen all in the same crucible WHICH IT MOST LIKELY IS!!

My answer is yes, good ventilation and protection is always needed when heating over 1000 degrees. Above that temperature, compounds can be made, whose lethal doses are measured in nanograms.
(as my chemical engineer friend never let's me forget)