Lichen grows on the surface of hornblende granite and causes it to breakdown at a faster rate. This is an example of. Weathering

Chemical.

Explanation:

Weathering can be defined as the physical and chemical breakdown of rock into smaller pieces called sediment. Weathering can be classified into two categories namely;

I. Physical weathering : it is the process of breaking rocks into pieces without affecting its chemical composition e.g temperature, abrasion and frost action.

II. Chemical weathering : it is the process of breaking rocks into pieces by chemical action which leads to changes in its chemical composition e.g carbonation, hydration, plant acid and oxidation.

In this scenario, Lichen grows on the surface of hornblende granite and causes it to breakdown at a faster rate. Thus, this is an example of chemical weathering

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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.