Formation of a precipitate in a chemical reaction is considered a??

Explanation:

Precipitation is defined as the creation of a solid from a solution. When the reaction occurs in a liquid solution, the solid formed is called the 'precipitate'. The chemical that causes the solid to form is called the 'precipitant'.

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Precipitate colors.

Goldblack

LeadYellow

luster is not a good characteristic to use by itself because luster is the property of minerals that indicates how much the surface of a mineral reflects light. the luster of a mineral is affected by the brilliance of the light used to observe the mineral surface.