Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
The rock yards around here sell such rock in several colors.
Cobbles are rounded rocks from about 1-1/2" up to about 10". Also called River Rocks. The more natural color is Noiyo Cobbles, mixed browns and grey, some cream-white, a few darker, charcoal, not really black. The more garish is Pami Cobbles, with more pink and purple tones. Another color is Yuba or Black and White. This, as the name implies, is a blend of black (or deep charcoal) and white (good, clear white).
Similar smaller rock is available with many colors and sizes. Some names are: Lodi, Yuba, Pami Pebble, Salmon Bay (a very yellow-gold blend, some pink), Red River, Sage Creek and many more.
One of the most expensive is sold as Mexican Beach Pebbles. These come sorted into colors, but are either pure flat black or a sort of rich purple that is not a glaring purple, a nice shade for a rock. These look stunning in ponds and water falls. More often we use them in pondless waterfalls or fountains. At the price, they need to be used in small amounts!
The names that a rock yard uses might be something that someone just made up, I have seen what appears to be the same rock under a couple of names.
Look for Rock, Soil, Brick, Mason, Landscape, Bark, Mulch and similar words to find a store near you. Most of these stores will sell by the pound, by the bag or by the truckload.
For the sand, I would suggest you look into pool filter sand rather than play sand. Pool filter sand is graded so most of the particles are the same size. It does not pack down in the tank like play sand, and needs much less rinsing, since all the fines have been sifted out. Ask at the rock yards, too about bagged sand. There is a company, Lapis Lustre that sells graded sand in many sizes. I would suggest about 30 mesh is probably the finest you might want in an aquarium. (That is the size of the local pool filter sand, and it works pretty well in my tanks.)