Can Crystals Melt?

Not all crystals are created equal, and when exposed to extreme heat, some may undergo unexpected transformations. Additionally, many commonly collected crystals on the market today are actually manufactured from plastic or resin. Many videos have been circling on social media of crystal collectors testing their own crystals under a flame to decipher weather they are natural or fake. Let's take a look at what minerals will burn in fire and what commonly faked crystals will melt. 

The Nature of Crystals:

Before we discuss how crystals react to fire, let's first understand what crystals are and how they form. Crystals are solid materials whose atoms are arranged in a highly ordered, repeating pattern, known as a crystal lattice. This arrangement gives crystals their unique structure and properties, including clarity, hardness, and color.

Crystals and Heat:

When subjected to heat, crystals can exhibit a range of responses, depending on their chemical composition and structure. While some crystals may remain unchanged, others may undergo physical or chemical alterations. It's essential to recognize these variations to handle crystals appropriately, especially when exposed to high temperatures.

Crystals That Burn

Certain crystals are combustible and will burn when exposed to fire. These include:

Sulfur: While not commonly recognized as a crystal in the traditional sense, sulfur forms crystalline structures and is highly flammable. When ignited, sulfur burns with a blue flame, emitting sulfur dioxide gas and leaving behind a residue of sulfur oxide.

Diamond: Surprisingly, despite its reputation as the hardest natural material, diamond can burn under extreme conditions. At temperatures exceeding 1400 degrees Celsius in the presence of oxygen, diamond will oxidize, transforming into carbon dioxide gas.

Ammonium Dihydrogen Phosphate (ADP): ADP is a synthetic crystal commonly used in optical devices such as laser systems. When exposed to high temperatures, ADP crystals can decompose and burn, releasing phosphoric acid and ammonia fumes.

Crystals That Melt

While some crystals burn when heated, others undergo melting or deformation. Common crystals that melt when subjected to fire include:

Selenite: Selenite, a form of gypsum, has a low melting point compared to other crystals. When exposed to heat, selenite may become soft and lose its crystalline structure, eventually melting into a liquid.

Halite:  Also known as rock salt, halite is composed of sodium chloride and readily dissolves in water. When heated, halite undergoes a phase change, melting into a liquid state.

Malachite:  Malachite, a copper carbonate mineral, is prized for its vibrant green color. However, when heated, malachite decomposes, releasing carbon dioxide and water vapor while leaving behind copper oxide residue.

Plastic and Resin Crystals

In recent years, the market has seen a surge in the popularity of crystals crafted from plastic or resin. These faux crystals mimic the appearance of genuine gemstones but lack their inherent properties. When exposed to fire, plastic and resin crystals will melt or burn, emitting noxious fumes and potentially releasing harmful chemicals into the air.

These plastic crystals are often found in the form of beads and cabochons, but can also be made into crystal clusters, towers, or spheres.

Commonly faked plastic crystals are : malachite, opal, rhodochrosite, rose quartz, (including other varieties of quartz), aquamarine and moldavite. 

Not sure how to tell if your crystals are real or fake? Check out this blog post that provides ways to identify fakes.

While crystals are renowned for their beauty and metaphysical allure, certain crystals may burn or melt when exposed to fire, while others remain unaffected. Additionally, plastic and resin "crystals" lack the inherent properties of genuine gemstones and will readily melt on contact with fire.