Answer: False.
Explanation:
The crystals of minerals are not always in the same size. They vary in their sizes. Some of them are large and some of them are extremely small.
The size of the crystals depends on the time it takes for cooling. If the crystals are cooled down very fastly then the size of the crystals is small.
If the crystals are cooled down slowly then the size of crystals are larger in size as compared to that of other crystals.