Crystal Formations and Their Meanings
Some shapes from: Crystal Earth Spirit

Crystals are the outer form of a mineral's inner order. Nearly every piece of rock of Earth is made of minerals, each of which is defined as a natural substance with a precise recipe and arrangement of atoms.

Crystal Point:  A single terminated crystal which can have many of the other features below.

Double Terminated: Features: A single crystal with a termination at each end.

Twin: Two Crystal Points which are joined together by their side facets from the base up. Also known as a Companion.

Cluster: A group of many Crystal Points which grow from the same base.

Geode: A hollow rock which contains hundreds of crystals growing inside it.

Key: A hexagonal or angular shaped recess usually on the side facets of a crystal and near the base.

Rainbow: A rainbow reflection inside the crystal, caused by a special flaw. Only seen when it catches the light.

Inclusion: Other minerals caught inside a crystal. May appear as darker material or bits suspended inside the crystal.

Phantom: A ghost like 3D image of a crystal point inside a crystal. Shows the earlier size before it grew bigger. Some crystals have multiple Phantoms.

Isis Face: A five sided face with a tall point at the top. Also known as an Isis Crystal.

Generator: A Crystal Point with six equal sized triangular faces and a very central termination.

Window: A diamond shaped extra face on a Crystal Point. Also known as a Sixth Face.

Bridge: Bridge Crystals have at least one smaller crystal sticking out and penetrating the main body of the crystal.

Channelling: Channelling Crystals have a large seven sided face with two small triangular face on either side and one triangular face directly behind the main face.

Record Keeper: Record Keeper Crystals have one or more triangles visible on one or more faces of the crystal.

Elestial: Elestial Crystals are multiple points growing from the same main crystal body.

Aggregator: Aggregator Crystals are large crystals partially or totally covered in smaller crystals.

See also:
Crystal Structure and Crystal Systems
5 Surprising Things to Know About Crystals
What Is the Difference Between Minerals and Crystals?
The World's 10 Most Deadly Minerals