Realgar & Orpiment
My old pal Bob Winokur has been doing some pyro-sleuthing and came up with a small stash of two pyro chemicals which are largely unobtanium now: Realgar and Orpiment, both arsenic compounds.
He was able to supply us with a little of each. You can order it below.
This has been an interesting process. Both of these chemicals are naturally occurring minerals. They are often found together, as you can see in the photo below:
The reddish crystals are realgar, and the yellow stuff is orpiment. They occur together and are very close to the same chemistry.
The powder we have was produced by first harvesting crystals of both chemicals and then grinding them into very fine powder. Suffice it to say, the whole process is mostly manual, expensive, and time consuming, and not much of it is available. To my knowledge, neither of these chemicals is produced synthetically in the US, if anywhere.
Realgar was most commonly used to produce white flames in fireworks before powdered metals such as aluminum, magnesium, and titanium became widely available. It was also used with potassium chlorate to make impact explosives. I have heard of crackling stars being made with it as well.
I do not suggest that you come to rely on either realgar or orpiment for any formulas that you want to make on a regular basis. They are both poisonous, of course, and I don’t know if we can or will continue to stock either chemical. Best to consider both of these as exotic pyro antiques, more a curiosity than a practical ingredient.
CAUTION: Both realgar and orpiment are sulfur compounds and will explode when mixed with chlorates. They are both arsenic compounds and highly poisonous. The resulting ash from burned pyro compositions is likely to contain water soluble arsenic oxide, which is considerably more toxic than either of the sulfides.
In addition to the information listed with each chemical on Skylighter.com, here is some historical info Dr. Winokur worked up on these two very old pyro chemicals.
You should treat the units of measure given in the tables below as parts by weight, unless otherwise noted. They do not necessarily add up to 100 in each column.