.LUCI File

The luci file extension appears to be mainly associated with the Amazon Kindle Fire, an e-book reading smart device with customized Google Android operating system.

The luci file is data container (simply folder) that stores e-books in mobi format.

Typically located in:

Download/mobi.luci

How to open:

You can use any file manager to view content of .luci container.

How to convert:

You cannot convert *.luci file (folder actually) to anything else, only the content.