Ornamental round beads are rather opaque minerals and all those rocks (amorphous aggregates of various minerals) with which decorative objects and jewelry can be made. Ornamental round beads are jasper, onyx, obsidian, aniolite, malachite, charoite, unakita, etc. Generally its price is not going to be very high and would be encompassed by the obsolete concept of semiprecious stone. One exception: lapis lazuli, being a rock, is so beautiful and appreciated that it should be considered as a precious stone. To illustrate the two previous points, if we take the example of quartz, we see that this mineral has precious stone varieties such as citrine or amethyst, and ornamental stone varieties such as jaspers.
- “Cat Eye” effect or Chatoyance: the wave of light produced by this effect, reminiscent of a cat’s eyelid, is caused either by the presence of inclusions or by channels oriented in only one direction. For the effect to be evident, the gem must be carved in cabochon (Style of carving with the upper part in the shape of a dome). It is observed in quartz, beryllium, tourmaline and apatite among others.
- Star effect or Asterism: in this effect a star with four to six points is observed that moves when moving a cabochon gemstone strongly illuminated. Some gems in which we can observe this effect are corundum, rose quartz and dropsied.
- Audacity: this effect consists of a bluish or whitish glow in the gem. We can find it in the, the adularia or moonstone and some ablates.
- Iridescence: consists of the appearance of certain colors of the rainbow in fractures or exfoliations of the crystal, by interference or diffraction of light. We can observe it in the rainbow quartz and the topaz.
- Consists of the round beads of the gem in a bright metallic color, it is presented mainly in blue and green gems.
- Opalescence: this effect is caused by the luminous reflection of short wavelengths, which produces a bluish, milky or pearly shine in the gem. It occurs in opal and milky quartz.
- East: it is presented by reflection of light in the surface layers of aragonite in the pearls.
Hardness of Gems
Its importance lies in that it relates to the permanence in time of the gem. Understood as the ability of gems to resist blows or friction with other materials its importance lies in that it is related to the permanence in time of the gem. This aspect is determined using the “Mohs scale”, this scale is a list of ten materials ordered according to their hardness from lowest to highest, based on the principle that a hard substance can scratch a softer, but not contrary.
This is why in the “Mohs Scale” there is an order of minerals to which hardness is attributed, starting with the talc that received the number 1 and ending with the diamond qualified with the number 10; in this way each mineral lines those who have a number lower than it and is scratched by those with a number equal to or greater than theirs.
- Precious round beads are all minerals whose crystalline forms are suitable and appreciated for use in jewelry. This term encompasses everything we consider precious round beads and most of what we know as semiprecious beads. Precious round beads would be therefore the citrino, the tourmalines, the sapphires, the amethyst, the aquamarine, the garnets, the diamond, etc. regardless of its greater or lesser price.
In any case, the old distinction between semiprecious round beads and precious round beads is still so widespread among merchants and consumers that for reasons of clarity and for all to understand each other well, we will continue to use the term semiprecious stone on our website. Of course, without forgetting that when we speak of a semiprecious stone we are talking about a gem in every rule.
So what is a gem? What causes it to increase its value?
We all have the mental image of what a gem is and represents. Put into words, a gem is any solid natural and inorganic material that possesses qualities of beauty, durability and rarity:
- The beauty of a gem lies in its color, its transparency, its brightness, its play of colors, its internal inclusions … any optical quality that makes it attractive to our eyes. For example, when choosing an amethyst we will look for a transparent stone of an intense purple color, but when choosing a moonstone we will not value its transparency -it is almost opaque by nature-, but its beautiful iridescences.
- The durability of a gem will be marked by its hardness to the scratch, its tenacity before the pressure and the blows, and its resistance to the most common chemical agents. In short, to resist daily use as part of a jewel, and that same jewel can pass from generation to generation. A bouquet of exotic flowers can be beautiful and rare, but it can never be part of an inheritance, a jewel with semiprecious round beads.
- The rarity of a gem will be marked by its greater or lesser natural scarcity and by the demand of that gem throughout history or in certain periods. The amethystIt was a highly valued stone until well into the 18th century, when Amethysts from the newly discovered deposits in Brazil began to arrive in Europe. This growing supply of amethyst reduced its price and its interest among the nobility and the emerging bourgeoisie, so that a beautiful gem that until then had enjoyed the category of precious stone came to be considered as semiprecious stone. Another example is jadeite jade, a gem that in the West does not attract much attention, and yet it is strongly demanded in Asian markets -mainly Chinese-, where jadeite is not considered a semi-precious stone, but as one of the most beautiful and valuable gems.