Bismuth Crystal Types

White graphic of a cubic Bismuth hopper crystal.
White graphic of Bismuth crystal in the shape of an elongated tower.
White graphic of a flat Bismuth crystal.
White graphic of a flat field of smaller repeating Bismuth crystals.
White graphic of a radial burst of Bismuth crystals around a nucleus.
White graphic of a circular, bowl-like geode of Bismuth crystals.

TOWERS

HOPPERS

GEMS

GEODES

FIELDS

BURSTS

Photo of blue, cubic Bismuth hopper crystals.
Black graphic of a cubic hopper crystal.

Hoppers

Hopper crystals are the technical name for the basic crystalline structure of Bismuth. Though terms like “Tower” and “Gem’ describe a nuanced physical form, they are all classified as hopper structures.

These 3-dimensional cubes form pyramidal funnels (hoppers) toward the center of the crystal, giving them a unique, otherworldly geometry.

Photo of multicolored, elongated Bismuth crystals.
Black graphic of an elongated Bismuth tower crystal.

Towers

Tower crystals are elongated hopper structures with a hollow interior. These often form when cooling Bismuth is in contact with a heat sink, causing a greater contrast in temperature between the crystal and surrounding molten metal.

Photo of three multicolored flat Bismuth crystals.
Black graphic of a flat Bismuth crystal.

Gems

Gems are geometrically flattened hopper crystals that often form near the top of cooling Bismuth, where the uppermost layer rapidly loses heat to the open air. Gem structures can be guaranteed to form with proper cooling technique.

A photo of three multicolored flat repeating field-type Bismuth crystals.
A black graphic of a repeating field of Bismuth crystals.

Fields

Fields are single pieces that are made of an amalgamation of crystals. This catch-all term includes all shapes of Bismuth crystals, with the common theme of geometric repetition.

A photo of a purple and gold burst of Bismuth crystals around a nucleus.
Black graphic of a burst of Bismuth crystals around a nucleus.

Bursts

Bursts structures are formed at a very specific time in the cooling process using a technique called “seeding”. In this process, a tiny, cooled Bismuth crystal is added to molten metal to jump-start the formation of new crystals. This causes elongated, aggressive crystals to form in a radius around the seed.

Photo of a blue and green bowl-like geode of Bismuth crystals.
Black graphic of a bowl-like geode of Bismuth crystals.

Geodes

Geodes are not a structure of their own, but a macro-structure containing crystals of all description. Geodes are created by pouring molten Bismuth out from a crucible before it completely cools, leaving behind a hemisphere of crystals similar to a natural stone crystalline geode.