Aquarium Rocks in Grey Fossil Gneiss for Layered Aquascapes, Terrariums, Ridges and Natural Paths

Give your aquarium or terrarium a strong natural foundation using Grey Fossil Stone, a metallic-grey gneiss marked by alternating feldspar crystals and fine mica layers. Its softly rounded, monolithic forms bring height and structure to Iwagumi layouts, mountain ridges, layered cliffs and paludarium backdrops.

Choose a tall statement stone, then arrange medium and smaller pieces to create perspective, transitions and natural-looking paths. Underwater, the grey tones deepen toward steel; when dry, the mica texture has a softer matte appearance. Mixed stones provide useful variation for building a cohesive hardscape rather than a row of matching shapes.

Key Features

• Natural feldspar and mica banding produces subtle striping and a cool mineral shimmer, adding visual depth under directional aquarium lighting.
• Rounded, tower-like formations make it easier to establish a focal point, stepped elevations and defined paths throughout the layout.
• The stone’s steely submerged color contrasts clearly against fine-leaf plants and mosses without overpowering their greenery.
• Pale sand emphasizes the mineral sparkle, while darker substrate creates deeper contrast for calm, architectural compositions.
• Suitable for aquariums and terrariums, the stone is safe for fish, shrimp, aquatic animals and terrarium animals when prepared and placed as directed.

Specifications

• Brand: WIO
• Material: Metamorphic gneiss with feldspar crystal layers and mica striping.
• Color: Metallic grey.
• Stone size: Mixed pieces approximately 1–12 in (3–30 cm).
• Available formats: Per pound, 4.4 lb Nano Bag, 11 lb Nano Box, 24 lb Standard Box and 46 lb Mega Box.
• Suitable environments: Aquariums and terrariums.
• Pre-use care: Rinse thoroughly and gently scrub before use.
• Placement: Lay substrate or a protective support beneath the stones to protect aquarium glass.
• Water chemistry: The stone may slightly raise pH and water hardness.

Build the arrangement securely, leave a small gap from the aquarium glass for maintenance access and monitor water conditions as part of your regular care routine. If pH or hardness rises, routine changes using RO or soft water—or an appropriate water softener—can help manage it.