Once again, if you've come looking for information your science project, you're going to be disappointed. And do not ingest hafnium, it will probably kill you in some horrible way - the effects listed below are entirely fictional.
Chance of Addiction: 25% per use
Cost: 75 gp
Hafnium is a weak substitute for genuine lanthanides, and is occasionally sold as such by unscrupulous narcotic merchants. It lacks many of the more positive effects of lanthanide use, and is much more habit-forming.
Reckless (-1d3 WIS, +4 morale)
Hallucinatory Visions (30% chance of causing effects of confusion spell during any combat)
Hunger for More - has a 50% chance of going for another dose if available. 4 doses in a short period of time is enough to cause the smoker to enter a coma for 1d3 days (75%) or simply die (25%).
The effects of hafnium last for 2d4 hours.
Addiction: Hafnium addicts may be identified by the metallic coating on their teeth.
Withdrawal: Hafnium withdrawal causes a loss of 1d3 DEX per day until withdrawal ends (20% chance per day) or 0 DEX is reached (at which point the addict dies). Lanthanide use will prevent hafnium withdrawal. Using hafnium (or a lanthanide) after withdrawal results in immediate re-addiction.