Polymineralic rocks are rocks formed by more than one type of rock forming minerals. The stress network of a polymineralic rock depends on the type of minerals found within the rock (hard and soft minerals), and the ratio in which they exist.

There are three kinds of rock: igneous, sedimentary, and metamorphic. Igneous rocks form when molten rock (magma or lava) cools and solidifies. Sedimentary rocks originate when particles settle out of water or air, or by precipitation of minerals from water. They accumulate in layers.

Mineralogist Frederich Mohs devised a scale from 1 to 10 to classify minerals by hardness. The harder a mineral is, the more likely it is to be valuable. If you can scratch the mineral with your fingernail, it has a hardness of 2.5 Mohs, which is very soft.

Preventing Countertop Damage

• Use hot pads or trivets for pans, crockpots, and electric skillets.
• Avoid using knives directly on Quartz countertops.
• Avoid cleaning with highly acidic or alkaline cleaners, such as nail polish remover, turpentine, oven cleaner, bleach, drain cleaners, dishwasher rinsing agents, etc.

Sometimes, to clean a mineral, or just see what it does, I take a rock I found, or some small vuggy piece I cracked open, and drop it in 3% hydrogen peroxide. It usually fizzes a few seconds, and stops. It is a real hodgepodge of small minerals, but chipped at one end, it looks more metallc,and feels heavier.

Soap and Water To clean quartz specimens a first good step is to scrub up one or two of them them with soap and water. Use liquid detergent soap, if you can, rather than some other kind and warm water. This will remove any easily removable dirt and can can often give you an indication of how to proceed.