By Material
Lava Stone / Volcanic Stone / Porous Volcanic Rock — Highly porous, absorbs essential oil well, long-lasting scent diffusion.
Clear Quartz / White Crystal — Transparent, non-porous, quick scent change.
Amethyst (Purple Crystal) — Purple tone, calming effect.
Rose Quartz (Pink Crystal) — Soft pink, romantic aesthetic.
Citrine (Yellow Crystal) — Yellow tone, energizing effect.
Fluorite (Green Fluorite) — Multi-colored, highly decorative.
Labradorite — Blue-gray sheen, premium look.
Moonstone — Soft milky white glow.
Marble Stone — Non-porous, surface diffusion only.
Ceramic / Clay Diffuser Stone — Can be porous or non-porous, versatile shapes.
Plaster / Gypsum Stone / Aroma Plaster — Good oil absorption, common for pendants and ornaments.
Mineral Salt Block / Salt Stone (Himalayan Salt Stone) — Air purifying.
Gravel / Pebbles / Crushed Stone / Chips — Decorative + diffuser, flexible quantity.

By Porosity
Porous Aroma Stone — Absorbs oil like a sponge, long-lasting diffusion. Examples: lava stone, gypsum, plaster.
Non-porous Aroma Stone — Does not absorb oil, quick scent change. Examples: crystal, marble, ceramic.

By Product Form
Aroma Stone / Aromatherapy Stone / Scent Diffuser Stone — General term.
Flameless Aromatherapy Stone / Fireless Diffuser Stone — No flame needed.
Aroma Pebbles / Scented Gravel / Fragrance Chips — Loose small stones.
Raw Stone / Rough Stone — Unpolished natural look.
Car Aromatherapy Plaster Pendant / Hanging Diffuser — Car-mounted.
Aroma Tablet / Scent Tablet — Flat disc shape.
2-in-1 Aromatherapy Stone / Dual-function Scent Diffuser Stone — Diffuser + decoration.
Essential Oil Diffuser Stone — Specifically designed for essential oils.

Most Common English Expressions
Scenario
Recommended Term
E-commerce title
Aromatherapy Diffuser Stone / Flameless Scent Stone
Product description
Porous Volcanic Aroma Stone
Daily conversation
Scent Stone / Fragrance Rock / Diffuser Rock
Professional term
Reedless Essential Oil Diffuser(vs. reed diffuser)

Quick Summary
The three most common types are:
1. Lava Stone (Volcanic Stone)
2. Crystal Stone (Quartz / Amethyst / Rose Quartz / Citrine)
3. Ceramic / Plaster Stone (Gypsum Stone)
All are collectively called Aroma Stone or Aromatherapy Stone in Englis