It may be Gasteraloe, one of the hybrids.

Roots will rot if the plant is potted in water-retaining soil, where its roots stay wet for too long and rot.

These plants should root easily, as long as there is no rot left in the stem. It should be of uniform and light color, creamy white or very light green. If there are any dark spots (could be ring-like, or blotches), you need to keep cutting thin slices off until there is no more dark left. (Can' tell from the 2nd photo - need sharp close-up pls.) Leave to callus for a while if it was too wet. That could be just an hour or so, or even overnight. Prepare well draining mix and pot with drainage hole(s). You can just set the cutting on top of potting mix, touching the surface. It doesn't need to be buried. Look thru THIS THREAD - CLICK ME. There are may photos and tips about rooting many different succulents (including a Gasteraloe which could be also your plant. This is in 2nd thread CLICK HERE, 1st post).

Last photo shows plant with very light center: that could be from inadequate light (easy to solve), or sometimes from rotting - more serious. If that is the case, leaves get that translucent color from being waterlogged, and feel soft (softer to the end where they attach). I can't tell for sure from your photo- larger, sharp close-up may help.

Ask any further questions you may have :)

I have cut it now and placed it on top of soil in a draining pot. The end was not moist so I placed on the side of the window. Will it need a darker place?

Warmth and lots of indirect light are what it needs.

Thanks a lot for your help!

I use powdered cinnamon on large cuts sometimes, as Karen suggested. Usually if it seems quite wet or was rotting. Make sure you don't cake it on, shake the excess as per Karen's comment.

Do not water for a while, I usually don't for few weeks. Plant without roots can't take in moisture, and could start rotting. Warmth and indirect light are great as per cactusmcharris :) for few weeks. Eventually, keep plant in good sunlight but make sure you acclimatize it to it. Mine spend whole winter under lights (not much sunlight during winter!) and outdoors, in full sun, when warm enough.

Watering rooted plants should be when potting mix is almost completely dry throughout. To make sure, you can check using bamboo-wooden skewer or chopstick or pencil. Insert deep into mix, leave in for 5 - 10 min (or longer if unsure). When pulled out, stick should be completely dry in order to water. If moist, wait. This will help to lean how often plant needs watering in mix you use, and you should be able to tell eventually, without using stick. Another way is to feel heft of the pot; wet mix is heavier than dry. If you do this every time before and after watering, it is easy to learn difference in heft. In cooler temps, it takes longer for mix to dry up.

If checking threads I posted links to (or any threads with lots of comments), make sure you click on: see xxx more comments.