Assertion: alkaptonuria's urine | /r/HasProperty | normal color
Facets:
value: usually
type: TEMPORAL
Source sentences:
text: Freshly voided urine is usually of normal color, but urine left standing turns brownish-black due to the gradual oxidation of HGA.
text: The urine is of normal colour when passed but rapidly darkens to jet black on exposure to atmospheric oxygen or other oxidative conditions.