[2][3][4] Idrialite usually occurs as soft orthorhombic crystals, is usually greenish yellow to light brown in color with bluish fluorescence.

[8] Idrialite was first described in 1832 for an occurrence in the Idrija region west of Ljubljana, northwestern Slovenia,[4] mixed with clay, pyrite, quartz and gypsum associated with cinnabar.

[10] The Curtisite variety is only slightly soluble in hot acetone, amyl acetate, butanol, petroleum ether.

[6] Curtisite is also associated with small amounts of a dark brown oil, that appears to be responsible for some of the yellow color and most of the fluorescence, and can be separated by recrystallization.

[10] Based on the composition, it was conjectured that the compounds were produced by medium-temperature pyrolysis of organic matter, then further modified by extended equilibration at elevated temperatures in the subsurface and by recrystallization during migration.