Crystal Lake is a naturally formed lake, a rarity in Southern California. It is snow and spring fed and has no other artificial means of being replenished. Geographically it sits in a bed of decomposed granite. There is a fissure located at the bottom of the lake that depletes its water during and after the rain and snow season. Because of this, the lake's depths vary dramatically from a mean low of 35 feet (10.7 m) to a probable high of 150 feet (45.7 m), depending on seasonal precipitation. The Lake is settled neatly in a bowl below the granite crags surrounding Mount Hawkins. In the past, the lake had amenities for picnickers, anglers, and swimmers. In 1969, a severe rainy season flooded the restrooms on the shoreline, and the water became contaminated to the point that the swimming facilities were closed. Subsequent rainy seasons flooded the small cabin that served as a summer residence for concessionaires who operated a snack stand from the lower level and patio, and by 1990 the facility was demolished. Over the past four decades, budgeting has limited the Forest Service's ability to maintain the lake and its feeder pipeline. Then years of drought reduced the lake’s water levels which continued microbiological contamination of the water, putting it off limits to any type of swimming at all. Following a good rainy season, the lake may be stocked with fish, typically rainbow trout from the government hatcheries. Despite high or low water levels, flocks of people line the lake to fish each summer. In the past the concessionaires provided boat rentals from a small dock that was attached to cables that ran onto shore. The dock could be raised and lowered during the year with the varying levels of the water. It was removed after the 1969 rains.

The best baits for this lake