hard drive - Windows 8.1 - Cannot Format Partition as NTFS: "There are no volumes"

I've got two hard drives in a system, one of which (disk 1) is the Windows boot disk, and the other (disk 0) has a partition (partition 1) that I'd like to format with NTFS. However, Disk Management won't let me; the option is greyed out. Diving into diskpart tells me that I cannot format the partition as NTFS because there is no volume selected. When I go to list the volumes to see which one to select, I see that none of them are what I want to format.

DISKPART> list disk
  Disk ###  Status         Size     Free     Dyn  Gpt
  --------  -------------  -------  -------  ---  ---
  Disk 0    Online         1863 GB      0 B        *
  Disk 1    Online          232 GB    35 GB              <-- This is the boot disk
DISKPART> select disk 0
Disk 0 is now the selected disk.
DISKPART> list partition
  Partition ###  Type              Size     Offset
  -------------  ----------------  -------  -------
  Partition 1    Unknown            500 GB  1024 KB      <-- Format this one
  Partition 2    Unknown           1363 GB   500 GB
DISKPART> select partition 1
Partition 1 is now the selected partition.
DISKPART> format fs=ntfs quick
There is no volume selected.
Please select a volume and try again.
DISKPART> list volume
  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
  Volume 0         System Rese  NTFS   Partition    350 MB  Healthy    System
  Volume 1     C   Root         NTFS   Partition    116 GB  Healthy    Boot
DISKPART> detail disk
ST2000DM001-1ER164
Disk ID: {DFD83667-1983-40B6-9EE3-03AFDD902518}
Type   : SATA
Status : Online
Path   : 1
Target : 0
LUN ID : 0
Location Path : PCIROOT(0)#PCI(1F02)#ATA(C01T00L00)
Current Read-only State : No
Read-only  : No
Boot Disk  : No
Pagefile Disk  : No
Hibernation File Disk  : No
Crashdump Disk  : No
Clustered Disk  : No
There are no volumes.

Neither of the listed volumes are 500 GB, which is the size of the partition that I want to format.