A Grain of sugar
1 milligram = 1/1000 of a gram. Very roughly, 29 grams in 1 ounce, so very roughly 464,000 milligrams in 1 pound. From the list you gave, it has to be the grain of sugar.
Rocks with a large grain size perhaps with angular grain shapes.
Yes simple as that.
They are rocks with a small grain size.
1.Grain Size 2.Grain Shape 3.Grain Pattern
Fine textured rocks have a type of grain referred to as aphanitic. This means that its grain is so tiny that it cannot be seen with the naked eye.
yes
They are eather fine grain or course grain. Granite are course Grain, Basalts are fine grains.
Rocks have color, grain, specific density, and relative hardness.
no
rocks with grains that can be identified with naked eye
Extrusive igneous rocks are usually fine grained.