Astereognosis is the inability to identify an object by touch without visual input. It is a form of tactile agnosia

Agnosia

Agnosia is a loss of ability to recognize objects, persons, sounds, shapes, or smells while the specific sense is not defective nor is there any significant memory loss...

 in which an individual is unable to identify objects by handling them, despite intact sensation

Sensation

Sensation is the fiction-writing mode for portraying a character's perception of the senses. According to Ron Rozelle, “. . .the success of your story or novel will depend on many things, but the most crucial is your ability to bring your reader into it. And that reader will be most completely...

. With the absence of vision (i.e. eyes closed), an individual with astereognosis is unable to identify what is placed in their hand. As opposed to agnosia, when the object is observed visually, one should be able to successfully identify the object.

Astereognosis is associated with lesions of the parietal lobe

Parietal lobe

The parietal lobe is a part of the Brain positioned above the occipital lobe and behind the frontal lobe.The parietal lobe integrates sensory information from different modalities, particularly determining spatial sense and navigation. For example, it comprises somatosensory cortex and the...

 or dorsal column or parieto-temporo-occipital lobe (posterior association areas) of either the right or left hemisphere of the cerebral cortex

Cerebral cortex

The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...

.