The substrate of opal was usually an opaque pale blue, while the inclusions flashed green to gold. Opals were usually cut cabochon or used as inlays, and a typical specimen had a base value of 1,000 gp.
Opals were considered sacred by followers of Lliira—appropriate for sacrifice, or to be consecrated for use, or recognized as boons or omens when found. White opals specifically were sacred to followers of Hathor.
Opals had a high affinity to magic and were used in casting numerous spells and in the creation of magic items, especially those that stored spells for later use. The most well-known example was the helm of brilliance. An example of a spell for which opals were required was the crown of brilliance spell used by archons and those blessed by the Seven Sisters. Opals were also used in rings of water walking.
Opals could be substituted for other, more scarce materials when constructing magic items because of their ability to release spells just as if they were cast normally, with no change in range, power, or effect. When enchanting opal or using it as part of a magical procedure, the best results were obtained at twilight.[note 1]
One extremely important caveat regarding opal: it was never to be used in creating items that attempted to combine fire and lightning. Doing so resulted in an immediate chain reaction/explosion in which a large bolt of chain lightning was released with the additional effect of two Melf's minute meteors released in random directions whenever a cascading target was hit.
- ↑ 1.0 1.1 1.2 Jeff Grubb and Ed Greenwood (1990). Forgotten Realms Adventures. (TSR, Inc), p. 138. ISBN 0-8803-8828-5.
- ↑ 2.0 2.1 2.2 Ed Greenwood, Eric L. Boyd (1996). Volo's Guide to All Things Magical. (TSR, Inc), p. 127. ISBN 0-7869-0446-1.
- ↑ 3.0 3.1 Ed Greenwood, Sean K. Reynolds, Skip Williams, Rob Heinsoo (June 2001). Forgotten Realms Campaign Setting 3rd edition. (Wizards of the Coast), p. 300. ISBN 0-7869-1836-5.
- ↑ Mike Mearls, Jeremy Crawford, Christopher Perkins, James Wyatt (2014). Dungeon Master's Guide 5th edition. (Wizards of the Coast), p. 134. ISBN 978-0786965622.
- ↑ 5.0 5.1 5.2 5.3 Jeff Grubb and Ed Greenwood (1990). Forgotten Realms Adventures. (TSR, Inc), p. 139. ISBN 0-8803-8828-5.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Ed Greenwood, Eric L. Boyd (1996). Volo's Guide to All Things Magical. (TSR, Inc), p. 46. ISBN 0-7869-0446-1.
- ↑ Sean K. Reynolds (2002-05-04). Deity Do's and Don'ts (Zipped PDF). Wizards of the Coast. p. 12. Archived from the original on 2016-11-01. Retrieved on 2018-09-08.
- ↑ Ed Greenwood, Sean K. Reynolds, Skip Williams, Rob Heinsoo (June 2001). Forgotten Realms Campaign Setting 3rd edition. (Wizards of the Coast), p. 301. ISBN 0-7869-1836-5.
- ↑ James Wyatt, Darrin Drader, Christopher Perkins (October 2003). Book of Exalted Deeds. (TSR, Inc), p. 95. ISBN 0-7869-3136-1.
- ↑ Richard Baker, James Wyatt (March 2004). Player's Guide to Faerûn. (Wizards of the Coast), p. 176. ISBN 0-7869-3134-5.
- ↑ Monte Cook, Jonathan Tweet, Skip Williams (July 2003). Dungeon Master's Guide 3.5 edition. (Wizards of the Coast), p. 233. ISBN 0-7869-2889-1.
- ↑ Ed Greenwood (July 1991). The Drow of the Underdark. (TSR, Inc), p. 94. ISBN 1-56076-132-6.