A cluster of colorless cubic fluorite crystals to 1 cm across with white acicular celectine.
Bloodshot Iolite. Known as the gemstone of the Vikings, Iolite was used by Norse and Viking explorers as a navigational aid, as a properly oriented stone would change color in relation to the direction of sunlight, allowing for crude navigation in the fog- enshrouded northern Atlantic waters where the direction of the sun was otherwise impossible to discern.
Quartz with Shattuckite inclusions - Namibia
Crazy Lace Agate (SiO2) is named for random lace-like patterns in the Agate layers. Most of this material is white or gray, but brown, red, and yellows are fairly common. The layers are sometimes porous enough that artificial colors can be added. From Mexico.