Consider this group of rocks: granite, marble, and gneiss.

What property was used to group these rocks?

color
hardness
streak
grain

The answer is Grain.

Explanation:

The four minerals that make up granite are feldspar, quartz, mica, and hornblende. Marble is a beautiful rock that is used by humans as building material and for decorative uses ... Rocks are classified into these groups by the way they were formed. ... Luster is a property of a mineral that tells how the mineral reflects light.

D) grain

Explanation: 2020 Edu (pls mark as brainiest)

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ca has a crystalline lattice with positive ions (since it is a metal, metals are positively charged) and electrons flow freely in its structure since the ca atoms have a large nuclear radius so the electrons are not tightly held, therefore the electrons can flow freely since they are not being highly attracted by the nucleus. moreover, one of the properties of metals are that they are conductors of electricity, thus proving ca is the element.