If it’s bright yellow and smells of eggs, matches, and/or flatus, it’s sulfur.

Physical Properties
Chemical formula S
Class Native element
Crystal system Orthorhombic
Habit Hexagonal tablets
Foliated masses
Scaly masses
Radiating or granular aggregates
Color Bright yellow
Hardness 1.5 to 2.5
Specific gravity 2.1
Cleavage Poor {101} and {110}
Fracture Conchoidal
Luster Resinous
Transparency Transparent to translucent
Streak White
Optical Properties
PPL Pale yellow
Often pleochroic
Extreme relief
XPL Extremely high birefringence
δ 0.29
Special properties Sulfurous odor
(bet you didn’t see that coming)
after Perkins, 354-355

Sulfur in Hand Sample

Hand sample of sulfur (it’s basically just a lot of yellow)

Sulfur in Thin Section

Stay tuned!

Further Reading

Sulfur at
Sulfur at