Diaspore (/ˈdaɪ.əˌspɔːr/) – also called diasporite, empholite, kayserite, or tanatarite – is an aluminium hydroxide oxide mineral, α-AlO(OH), crystallizing in the orthorhombic system and isomorphous with goethite.

[4] It may be readily distinguished from other colorless transparent minerals with a perfect cleavage and pearly luster (e.g. mica, talc, brucite, and gypsum) by its greater hardness of 6.5–7.

[5] The mineral occurs as an alteration product of corundum or emery and is found in granular limestone and other crystalline rocks.

Well-developed crystals are found in the emery deposits of the Ural Mountains and at Chester, Massachusetts, and in kaolin at Schemnitz in Hungary.

The name, which was coined by René Just Haüy,[6] is from the Ancient Greek διασπείρω meaning "to scatter", in allusion to its decrepitation on heating.