Crystal Caves was a game written and by Apogee. In the game, you act as Mylo Steamwitz, a miner who wants to get rich quick. In order to invest in some ridiculous Get-rich-quick schemes (including, but not limited to, starting a "Twibble" farm), he travels to the Altairian star system and ventures into the caves in the planets there to harvest large, naturally grown crystals.
This game was released in three episodes--the first one being shareware.