My allure went a long time ago...
C&C welcome - but don't ask about my allure.
The first and last shots were done on black perspex to get the reflection. I used a black backdrop (Lastolite fold-out) and they were lit with two studio lights at 45deg to the front. All four shots were taken with Canon 5D Mk1, and Sigma 105mm.
For these next two I used my shoot-through method. The item is sandwiched between two studio lights. The one behind the object is diffused and forms the white backdrop. It also lets a lot of very soft light through the translucent parts of the object, and gives a very nice finish. The light in front of the object (behind the camera) just 'balances' the light levels - otherwise I'd just end up with a white-out and a dark object.