A special type of oil lamp that is very often not recognized is an opium lamp. 
An opium lamp is an oil lamp designed to facilitate the vaporization and inhalation of opium. 

Opium lamps differ from regular oil lamps for lighting in that they or made to channel a precise amount of heat upward through their funnel-shaped chimneys. An opium pipe was held over the opium lamp, causing the opium to vaporize and allowing the smoker to inhale the vapors.

Opium lamps were mainly crafted in China before 1949; the government brought opium smoking to an abrupt halt after 1949. Small-scale production of opium lamps continued in Hong Kong and Southeast Asia, including Vietnam, until the mid-1960s.

Opium lamps mainly were crafted from one or more types of metal such as silver, brass, or paktong, an alloy known as nickel silver. Often the metal parts of the lamp were adorned with cloisonne. The opium lamp's distinctive chimney was made from glass.

Due to opium eradication campaigns in the nineteenth and early twentieth centuries, antique and authentic opium lamps are now rare.

Occasionally, opium lamps are offered on eBay or other online sales sites. Only regularly, these are not old, but more recent replicas, below three different opium lamps. 

Authentic opium lamp

The one below is an authentic opium lamp; I couldn't find a second one online either with a beautiful mosaic inlay.

Questionable opium lamp

Below is a lovely example of an opium lamp that gives a great shadow/light effect. But I've had three of these now; this says enough.

In all probability, this is a more recent opium lamp, I think from the 60s-70s.

Recent, replica opium lamp

The third in the series is different build quality than the first two. There is also a stamp on the bottom, Hong Kong.
I expect this to be a recent replica.