#precious stone
- Adamant — An archaic, rare, or regional form of the noun 'diamant' (diamond), or used in ancient legends and religious texts to designate a mythological precious stone of extreme, indestructible hardness, often confused with diamond or loadstone. This structural term serves in ancient texts as a symbol for steadfastness, absolute purity, spiritual moral resilience, or unyielding harshness.
- Amazonite — A green to bluish-green variety of microcline feldspar, crystallizing in the triclinic system, widely used as a semi-precious ornamental gemstone. Its unique color and vitreous luster are structurally caused by microscopic trace amounts of lead and water within the crystal lattice.
- Amethyst — A violet, purple, or lilac semi-precious macrocrystalline variety of quartz, whose coloration is due to iron and titanium impurities combined with natural irradiation within its trigonal crystalline structure. This structural mineral is widely utilized in jewelry, high-end decorative crafts, and is valued in crystal healing for its symbolic calming properties.
- Azurite — A natural basic copper carbonate mineral with a monoclinic crystal structure, characterized by an intense, glossy, vitreous blue color and a famous chemical instability, often transforming into malachite under the influence of moisture. This structural mineral is found in the oxidation zones of copper ore deposits, historically used as a fine paint pigment and currently as a semi-precious stone for jewelry or decorative objects.