Are you looking for a unique way to make your aquarium really stand out? Onyx Sand is a great way to make a statement Pitch-black; sparkling sand; completely safe for fresh and salt water. This sand does have a slight buffering capacity; as well. All natural; no artificial coatings. Ideally suited to planted aquaria and most effective when alone. However it may be mixed with other gravel to make a completely unique aquascape. Gravel and substrate color may differ or vary due to your computer monitor's resolution.