Onyx Lamp vs Alabaster Lamp: What Is the Difference?

In the lamp trade, "onyx" usually means banded calcite, a calcium carbonate stone of about 3 on the Mohs scale. Alabaster for lighting is usually gypsum, softer at about 2. True mineral onyx is banded chalcedony, far harder. Teeshaa makes alabaster lighting and does not sell onyx, so this is a neutral comparison.

key facts.

• In mineralogy, onyx is banded chalcedony, a silica mineral of Mohs hardness 6.5 to 7.
• Lamps sold as onyx are usually banded calcite, often called onyx marble or Mexican onyx, with Mohs hardness about 3.
• Gypsum alabaster, the type Teeshaa uses, is calcium sulfate with Mohs hardness about 2 and can be scratched with a fingernail.
• The word alabaster also covers calcite, so the same banded calcite can be sold as either name.
• Both stones are translucent and both belong indoors, away from water.
• The most reliable question to ask any seller is which mineral the stone is.

what does onyx lamp actually mean?

It depends on who is using the word. A mineralogist means black-and-white banded agate, a form of chalcedony. A lamp seller usually means a translucent banded stone that is softer and more widely available.

The mineral reference for onyx notes that the name has also been applied to banded calcite found in Mexico, India and other places, and to materials called "cave onyx" and "Mexican onyx". Alabaster references describe "onyx marble" as a name for calcite alabaster, usually a compact, banded travertine. The term is used loosely in the trade, so a listing that says onyx may not tell you the mineral.

If a listing means true onyx, the stone would be chalcedony. If it means onyx marble or Mexican onyx, it is calcite. Ask the seller to name the mineral, not only the trade name.

how do onyx and alabaster differ as stones?

They differ in chemistry and hardness. Commercial onyx is calcite, a carbonate that reacts with acids. Gypsum alabaster is a sulfate, softer, and sensitive to water and heat. True onyx is silica and much harder than both.

Property	True onyx (chalcedony)	Lamp-trade "onyx" (banded calcite)	Gypsum alabaster
Mineral	Silica, banded chalcedony	Calcium carbonate, CaCO3	Calcium sulfate dihydrate
Mohs hardness	6.5 to 7	About 3	About 1.5 to 2
Fingernail and knife	Neither marks it	Resists a fingernail, yields to a knife	A fingernail scratches it
Acid	Silica, not a carbonate, so no fizzing like calcite	Dissolves and fizzes in acid	Does not fizz like calcite
Water	Silica, not a soluble salt like gypsum	Indoor use only	Slightly soluble, indoor use only
Typical look	Black and white bands	Bold bands in cream, honey and brown	Cloudy white or cream, grey veins, amber inclusions

For the wider stone family see the guide to alabaster, marble and onyx lighting, and Spanish alabaster vs Egyptian alabaster for the gypsum and calcite split.

how do they look and glow when lit?

Banded calcite tends to show its stripes as lighter and darker bands when lit from behind. Fine-grained gypsum alabaster tends to scatter light into a cloudy, even glow. Both are translucent, and both change appearance between unlit and lit.

A hotspot is a brighter patch on the stone directly in front of the light source. Whether one appears depends mainly on wall thickness, the distance between source and stone, and any diffuser inside, more than on the mineral. Thin walls glow brighter and show more of the internal structure. Thick walls look denser and darker.

Ask for photographs of the actual lamp switched on, in a dim room, as well as unlit.

which is easier to live with?

Banded calcite resists scratching better because it is harder. Gypsum alabaster marks more easily and dislikes moisture and heat. Neither is a rugged material, so both suit dry indoor rooms and gentle handling.

• Scratches and knocks. Conservation sources describe alabaster as easily broken, bruised, abraded and scratched. Calcite is harder, but still yields to a knife.
• Water. Alabaster references say its solubility in water makes it unsuitable for outdoor work. Polished gypsum surfaces are especially vulnerable to moisture.
• Acids. Calcite dissolves in acid, so acidic spills and cleaners can mark it.
• Heat. Conservation sources note that alabaster loses translucency when heated, so keep any stone lamp clear of heaters and stoves.
• Weight. It depends on size, wall thickness and the base or metalwork more than on the stone name. Ask the seller for the finished weight, and use a licensed electrician or structural advice for anything hung from a ceiling.

For Teeshaa pieces the care wording is: a soft, dry or lightly damp cloth, no harsh chemicals or abrasive cleaners, and the care guide supplied with the piece. For any other lamp, follow the seller's instructions. See the care page.

when is onyx the better choice, and when is alabaster?

Choose banded calcite when you want a bold striped pattern or a surface that resists scratches. Choose gypsum alabaster when you want a soft, diffused glow with cloudy depth. Your room, light level and habits decide it.

If you want	Better fit	Why
A bold, graphic banded pattern	Onyx (banded calcite)	The stripes are the character of the stone
A lamp that resists scratching in a busy room	Onyx (banded calcite)	Hardness about 3 against about 2, though both are soft stones
A soft, even, cloudy glow	Gypsum alabaster	Fine grain scatters light into a diffused wash
A quiet, sculptural look when switched off	Gypsum alabaster	Pale, cloudy stone reads soft rather than patterned
A bathroom vanity, open balcony or splash zone	Neither	Both are indoor stones that dislike water
A spot near a heater or stove	Neither is ideal	High heat reduces translucency in alabaster, so keep any stone lamp clear of it
Certainty about the stone	Whichever seller names the mineral	Trade names such as onyx marble are used loosely

which rooms suit each stone?

Either stone suits a dry bedside table, a living-room console or a hallway shelf. Pick by the light you want. Gypsum alabaster suits rooms where you want a calm, ambient glow. Banded calcite suits a statement piece where the pattern is the point.

Neither stone is a task light. Pair a table lamp with downlights or a reading light where you read or cook. In humid or coastal Indian homes, keep both away from bathrooms, splash zones and open balconies.

how Teeshaa fits.

Teeshaa's lights are made in Spanish alabaster, a naturally translucent gypsum stone. Clouding, veining and mineral inclusions differ block to block, so no two pieces are the same, and stone is reviewed unlit and lit. The Pebble Lamp pairs Spanish alabaster with black Gorara stone.

For table lamps, see the alabaster table lamps, including the Totem Table Lamp at 49 cm tall, the Essenzo Porcini Table Lamp and the Pebble Lamp. The table lamp guide covers size and placement, and the material page explains the stone. Browse everything under alabaster lighting.

frequently asked questions.

Is an onyx lamp the same as an alabaster lamp?

No. Lamps sold as onyx are usually banded calcite, a calcium carbonate stone of about 3 on the Mohs scale. Alabaster used for lighting, including Spanish alabaster, is usually gypsum at about 2. The trade also calls some calcite alabaster, so ask which mineral it is.

Is onyx harder than alabaster?

True onyx, which is banded chalcedony, is far harder than alabaster at 6.5 to 7 on the Mohs scale. The calcite sold as onyx in lamps is harder than gypsum alabaster, about 3 against about 2, but it is still a soft stone that a knife can scratch.

Does onyx glow better than alabaster?

Neither glows better in general. Banded calcite shows contrasting stripes when lit, while fine-grained gypsum alabaster gives a cloudy, even glow. Wall thickness and the light source matter as much as the stone, so judge a lamp by photographs of that piece switched on.

Can I put an onyx or alabaster lamp in a bathroom?

It is better not to. Both are indoor stones, and alabaster references note that water solubility makes the stone unsuitable for outdoor work. Gypsum is especially sensitive to moisture. Keep either lamp away from splash zones, shower areas and open balconies, and in humid homes choose a dry, ventilated room.

How can I tell what stone a lamp is made from?

Ask the seller to name the mineral, not only the trade name, since onyx, onyx marble and alabaster are used loosely. Gypsum can be scratched with a fingernail, while calcite resists it. Do not test a finished lamp by scratching. A clear written description of the stone is the safer route.

Reviewed by the Teeshaa studio, 19 October 2026.

sources.

• Wikipedia: Onyx
• Wikipedia: Alabaster
• Wikipedia: Calcite
• Conservation Wiki: Alabaster