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Holland Glass & crystal inc. - Cristallerie Holland inc
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INFORMATION ON CRYSTAL

Stock nos. beginning with:
V - 24% lead crystal from Poland, some with “Tiara” label
W -“Tiara” lead-free crystal from Poland.
G - 24% lead crystal from Germany.
P – “Lexcel” lead-free crystal from Portugal.

What is crystal?
Natural mountain crystal, which is found in the hollows of rock formations, is a semi-precious stone of great hardness. A very poor heat conductor, it’s constantly cool to the touch. Because of this property, and the stone’s visual resemblance to ice, it was called “crystal” after a Greek word meaning ice.

The crystal we find in the gift and tableware market is glassware, called crystal because of its clarity, fine quality and high refractive power. Lead oxide is often added to the original ingredients of silica sand, potash and cullet – although some products, justifiably called crystal for their purity and beauty, do not necessarily have to contain lead oxide.

What is lead crystal?
Lead crystal is the term used for glass that combines silica, potash, cullet AND lead oxide. The lead content softens the glass and makes it easier to cut. At the same time, the product becomes more sensitive to light and acquires its characteristic and inimitable sparkle.

What bearing does 10, 15, 24, and 30 percent, etc., lead content have on the finished product?
Research and experience have shown that 24 percent lead oxide is a good percentage for cut crystal, although many cutters prefer 18 percent so the product does not become too soft and ”dust” under the cutter’s wheel. The fact that a product has more than 24 percent lead content does not mean it’s of superior quality. To the contrary, it may chip more easily and may acquire a bluish tinge in time.

What is pressed and overcut crystal, as opposed to mouth blown and hand cut crystal?
Most hollow pieces can be mouth blown. The mouth blowing is done by the traditional age-old methods and are always more expensive obviously than machine pressed. The pattern is then cut into the crystal on the cutting wheel, hand guided by a master craftsman. Pressed crystal has the “cut pattern” introduced by pressing it into the glass while the product is still in a near-molten state. Overcut crystal is “pressed crystal” which has received its details and finishing touches from a master cutter who is a hand craftsman.

What is the melting point for crystal?
Lead crystal melts at 1,100-1,200˚C.and is workable at 400-600˚C.

How much time does a glass-blower require to produce the basic product before it’s cooled?
Depending on the piece, the time can be as little as 45 seconds or as much as five minutes.

What happens to broken or defective pieces?
They are remelted and become “cullet”.

Does the delicate ring produced by tapping a piece of crystal identify quality?
Not at all. The sound is created from a variety of things – size, shape, thickness, etc. Even similar pieces can have a different ring.

What methods of polishing crystal are used?
Crystal can be polished by means of acid, or by wheels. The wheels are soft wood or, when available, cork.

Why is rich-cutting so expensive?
The price is based solely on time and skill. Lead content has little bearing on price. Some highly decorative pieces may take 25-30 hours to cut, absorbing as many as 8,000-10,000 cuts.

How is engraving achieved?
Engraving can be done by hand using a small copper engraving wheel, or by means of automation. In the latter process a magnetic tape transfers the pattern to a computer which in turn engraves the product using a diamond cutting ball. Automated cutting can accommodate up to 10 glasses at a time very quickly.

What are the most difficult pieces to produce?
In lead crystal they include wine and liqueur decanters with handles. Baskets are also difficult as are jugs which require great skill to perfect their shape. In stemware the hardest part of production is the stem and foot.

When was present-day lead crystal discovered?
Lead crystal was discovered in England approximately 300 years ago and was perfected over the years by skilled craftsmen in several countries.

 





 

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