Pumice is a fine-grained volcanic rock. It is very light grey to medium grey in colour. It contains a lot of empty gas bubbles, so it is very light and looks rather like a sponge.

approximately 3 μm

Pumice is considered a volcanic glass because it has no crystal structure. Pumice varies in density according to the thickness of the solid material between the bubbles; many samples float in water.

Chemical Characteristics—Pumice is an inert aluminosilicate material composed primarily of silica and A1-oxide but may also contain metal oxides, calcite, or salts.

Most holey rock and lace rock will probably be limestone based, and also raise pH and hardness. Igneous rocks (granite, basalt, lava rock, pumice, obsidian, etc.) are almost always inert/safe.

CR Minerals Pumice Crystalline silica dust is classified as Hazardous. Dust in/on the product or generated by crushing or abrasion may form crystalline silica of respirable size that is small enough to be inhaled into the lungs.

Extrusive igneous rocks cool much more rapidly than intrusive rocks. Some extrusive igneous rocks cool so rapidly that crystals do not develop at all. These form a glass, such as obsidian. Others, such as pumice, contain holes where gas bubbles were trapped in the lava.

Obsidian: Obsidian is actually black volcanic glass. Due to its dark color and glass composition, obsidian does not fade in sunlight and, in fact, it is often found naturally outdoors. Clear Quartz: Perhaps the quintessential cleansing crystal, clear quartz does not fade due to its not being pigmented at all.

Articles should be cleaned with clear water and soap or a mild detergent. Abrasive tools or utensils must not be used, as they will damage the polished surface. For long-lasting beauty, obsidian tableware should be washed by hand in warm water. As with glass and crystal, it is better if the wash water is not too hard.

Black Obsidian will do just fine in a salt water bath. This article can give you more information on crystals that can be damaged by water.

Healing Properties Obsidian is truth-enhancing. A strongly protective stone, it forms a shield against negativity. It blocks psychic attack and absorbs negative energies from the environment. Obsidian draws out mental stress and tension.

It is good to wear one especially when you are traveling overseas as a protective amulet. It can also aid in reducing stress level because it helps one to balance your energy. With balanced thoughts, it helps you to think well and manage your emotion, so you are less drawn into unnecessary disputes or quarrel.