Core Aragonite
Core Aragonite (#A2AAA4) is a balanced neutral with a mono character. It's a grayscale value, at home in typography, dividers, and the structural layer beneath stronger colors. Its HSL profile (135°, 4%, 65%) places it in the muted band at a mid lightness. It works well as secondary text, borders, and placeholder states. A reliable middle gray that reads cleanly in either light or dark contexts. Pair it with almost any saturated accent. It's built to sit underneath or behind stronger colors without fighting them.
Etymology
Old French cor, heart / center — adjectival usage of core. As a color modifier, core implies a neutral-and-central-and-essential quality where the hue carries the visual register of Bauhaus-and-Mondrian-De-Stijl central-and-essential-design foundational-element-and-base-color. Sits at the neutral-and-foundational end of the grid, parallel to central and essential in usage.
CaCO₃ orthorhombic calcium-carbonate polymorph — the principal mineral of mollusk-and-coral skeletons, particularly the Bahamian-coast aragonite ooid-sand bars. Aragonite color refers to a freshly cleaved Bahamian-coast aragonite ooid-sand grain: a pale cool gray with the glassy finish of orthorhombic-system calcium-carbonate with the characteristic aragonite ooid concentric-shell structure.
Closest matches
The nearest named color in three reference sources, ranked by perceptual distance (ΔE76 in CIELAB). ΔE < 1 is imperceptible to most viewers; ΔE > 10 is clearly different. When two sources point to the same hex they’re merged into one tile; click any to open that color’s page.
Variations
Click any swatch to exploreHarmonies
This color has effectively no chroma (OKLCH C = 0.012) — it’s on the grayscale axis. Hue rotations don’t change a grayscale color, so complementary, analogous, triadic, and split-complementary all reduce to the same value. They aren’t shown because four identical tiles would be misleading.
Accessibility
How this color appears to viewers with the four major color-vision-deficiency types. Computed via the Machado (2009) physiologically-based model. If a tile matches the original, the color reads the same to that viewer.
The color used as foreground text against pure white and pure black, with the contrast ratio and WCAG 2.1 grade. Aim for AA (4.5:1) for body text and AA Large (3:1) for 18 pt+ headlines; AAA (7:1) is the gold standard for long-form reading surfaces.
Wide gamut
The CSS Color 4 wide-gamut form of this color. Both swatches render the same color on every display — the P3 form only diverges from sRGB when a designer pushes channels outside sRGB's reach.
This color sits well within the sRGB cube. P3 and sRGB share the gray axis and most desaturated tones, so a P3 display renders this identically to an sRGB display.