Gem Profile- Glass, Crystal and Quartz

by Judy Ellis

Let's talk Glass, Quartz and Crystal:

A couple of years ago, Dale Armstrong did a series of gem profiles about quartz. In her profiles she touched on several different types of glass that have been labeled as quartz. Technically they were since both quartz and glass have the same base of silicon dioxide (SiO2), however, the main difference between glass, quartz and crystal is the arrangement of the atoms and the basic molecular structure of the material.

Glass is considered an amorphous solid; it doesn't have a crystalline structure and is made primarily of silicon, potash, lime and soda.

Quartz crystals are pure silicon dioxide and found within the earth.

Crystal is made with silicon, sodium and lead, making the atoms in the glass line up and form crystals which allow it to be carved and faceted easier than glass.

In jewelry making, we use all three materials; glass, quartz and crystals. Today I thought it would be nice to touch on all three.

What is Glass?

Glass beads are made from a thin reed, or cane, which is then cut, drilled, and polished.

The most familiar types in jewelry making are seed beads and fire-polished Czech beads.

Czech glass beads are faceted and then heated in a furnace to smooth rough edges. Care is needed during this process, or the beads can melt.

These beads are amorphous, lacking the brightness and light-refraction properties found in crystal.

What is Quartz?

Quartz, a naturally beautiful stone, comes in a range of colors from rose to smoky and has been valued for centuries in jewelry and other gemstones.

Some of the most familiar quartz gems include amethyst, citrine, smoky quartz, and rose quartz.

The color of quartz depends on the trace ions present as silicon dioxide crystallizes.

For example, iron ions are responsible for the rich purple color in amethyst.

Rose Quartz Necklace. Created by Peggy L. Marzano.

What is Crystal?

Crystal is similar to quartz because it has a crystalline structure and is made of silicon dioxide.

The key difference is that crystal is man-made, like cubic zirconia, and has a chemical composition similar to diamonds.

Crystal is glass made with silicon, sodium, and lead. The lead causes the atoms in the glass to align, transforming it from an amorphous solid into a true crystal.

In ancient times, trace amounts of lead were used to color glass, but not enough to create crystal.

This process was developed in 1676 when Englishman George Ravenscroft added a higher concentration of lead oxide, producing clearer, more durable glass suitable for carving and faceting into beads and other decorative items.

This unusual specimen comes from Tibet. Notice not only the exotic crystal scepter growth, but also the clay inclusions within the bottom crystal.

About Crystal:

In 1891, Daniel Swarovski invented a machine to cut and facet crystal beads, enhancing the refractive and reflective qualities that give us Swarovski Crystal.

Swarovski Crystal contains up to 32% lead dioxide.

Adding lead to glass not only turns it into crystal but also lowers the melting point, making it softer and easier to carve and facet.

The lead is also what gives the crystal its signature clarity and sparkle.

Swarovski crystals

Gem Profile- Glass, Crystal and Quartz

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