Quartz Quadrant

Quartz Quadrant is the fourth round in Sonic the Hedgehog CD. The boss of the third zone is Dr. Robotnik in a conveyor belt trap room.

Present
Quartz Quadrant is an aqua-colored mine bustling with machinery, and is in the process of extracting crystals (most probably quartz hence the round's name) on conveyor belts and platforms for an unknown purpose. Some of the quartz is being transported while some are left lying around. The outdoor area features a swamp where the quartz are being shipped off to whatever far-off land they are designated to.

Past
In the past, it is a green, peaceful cavern where a very large quantity of crystals remain in a type of ooze. Outside these caverns, a swamp/bayou is present showing dead driftwood in the waters and forestry at the bottom of the zone. Conveyor belts are present, but are not being used for any purpose just yet.

Bad Future
In the Bad Future, it is an over-mechanized olive green rusted mine under Dr. Robotnik's influence where absolutely no crystallized quartz can be found. A river of what appears to be lava (but could possibly be melted quartz) runs through the bottom of the zone, and a factory-like dystopia stretches for miles under a fiery sky. The factories may or may not be attempting to create artificial quartz, but it seems that their operations might have backfired in some way.

Good Future
In the Good Future, it is an underground, golden-colored utopia that is seemingly hidden from society. All of the mining has ceased by this point, and opulent towers of quartz gleam through the darkness. Outside of this wonderland of quartz, there are futuristic domes with mountains and forestry beyond them. A wall is seen at the mid-height section of the zone featuring the same type of domes; it may be there to keep unwanted outsiders away from the underground city. There are no active mines or swamps here in the good future, but more quartz are found here than in any of the timezones.

Trivia

 * Sonic CD has a time travel theme, and, fittingly, quartz is used in many modern analog watches.
 * In fact, analog clock faces are commonly used to show passage of time (this was present in the opening of Sonic Generations.)