Arsenic (as you probably already know) is infamous for its use as a poison. During the 19th century, arsenic’s frequent use as a means of offing one’s relatives earned it the name, “inheritance powder”. Element number 33 also formerly saw use in green pigments, rat poison, glass manufacturing, and in pesticides. Gradually, arsenic has been phased out of these applications. The compound gallium arsenide (GaAs), though, is still widely used as a semiconductor material in a wide variety of electronic devices.
Currently, my only samples for arsenic are mineral specimens.
Shown above are two crystals of adamite (Zn2AsO4OH), mined in Mexico. As interesting as this sample is, though, it is overshadowed by my other arsenic mineral sample.
This interesting looking sample from Romania includes silver stibnite (Sb2S3) and clear baryte (BaSO4). The arsenic content comes from the small crystals of red realgar (As4S4) and the black sprays of oxidized native arsenic. Photos don’t really do justice to how cool this sample looks in real life, and I consider it to be one of the most visually appealing samples in my collection.