Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
207 words
A process for producing clear, unsmoky amethyst crystals which comprises (a) growing colorless quartz crystals by a hydrothermal method of a temperature drop on crystalline quartz seed plates oriented parallel to the crystallographic planes of the major {1011} and minor {1101} rhombohedrons using crystalline quartz having an aluminum impurity content of at most 5.10 - 3 weight percent as a charge; said growing being effected from aqueous solution of potassium carbonate or potassium hydroxide, the solution having a concentration ranging from 4 to 7 weight percent and containing iron in the form of a substance selected from the group consisting of metallic iron, and its oxide and hydroxide compounds, in an amount ranging from 5 to 30 g/l of the solution and an oxidizing agent selected from the group consisting of lithium nitrate, lithium nitrite and manganese nitrate in an amount ranging from 1 to 10 g/ml of the solution of potassium compounds; said growing of colorless quartz crystals being effected at a crystallization temperature within the range of from 300° to 500° C. under a pressure of from 200 to 1,700 kg/cm 2 and a crystal growth rate of from 0.05 to 0.5 mm/day; and (b) exposing the thus-grown colorless quartz crystals to an ionizing irradiation.
Claim 2
Dependent Claim
207 words
A process for producing clear, unsmoky amethyst crystals which comprises (a) growing colorless quartz crystals by a hydrothermal method of a temperature drop on crystalline quartz seed plates oriented parallel to the crystallographic planes of the major {1011} and minor {1101} rhombohedrons using crystalline quartz having an aluminum impurity content of at most 5.10 - 3 weight percent as a charge; said growing being effected from aqueous solution of potassium carbonate or potassium hydroxide, the solution having a concentration ranging from 4 to 7 weight percent and containing iron in the form of a substance selected from the group consisting of metallic iron, and its oxide and hydroxide compounds, in an amount ranging from 5 to 30 g/l of the solution and an oxidizing agent selected from the group consisting of lithium nitrate, lithium nitrite and manganese nitrate in an amount ranging from 1 to 10 g/ml of the solution of potassium compounds; said growing of colorless quartz crystals being effected at a crystallization temperature within the range of from 300° to 500° C. under a pressure of from 200 to 1,700 kg/cm 2 and a crystal growth rate of from 0.05 to 0.5 mm/day; and (b) exposing the thus-grown colorless quartz crystals to an ionizing irradiation.
Claim 3
Dependent Claim
72 words
A process as claimed in claim 1, wherein said colorless quartz crystals are grown on seed plates oriented parallel to the crystallographic planes of the major rhombohedron, said aqueous solutions of potassium compounds have a concentration of 5 weight precent, and the crystal growing is effected at a crystallization temperature at 360° C. under a pressure of 1,500 kg/cm 2 and at a crystal growth rate of from 0.1 to 0.2 mm/day.
Claim 4
Dependent Claim
71 words
A process as claimed in claim 1, wherein said colorless quartz crystals are grown on seed plates oriented parallel to the crystallographic planes of the minor rhombohedron, said aqueous solutions of potassium compounds having a concentration of 5 weight percent and the crystal growing is effected at a crystallization temperature of 360° C. under a pressure of 1500 kg/cm 2 and a crystal growth rate of from 0.2 to 0.4 mm/day.
Claim 5
Dependent Claim
133 words
A process as claimed in claim 1, wherein said crystalline quartz having an aluminum impurity content of at most 5.10 - 3 weight percent is synthetic quartz crystals which are grown by a hydrothermal method of a temperature drop on crystalline quartz seed plates oriented parallel to the crystallographic planes of pinacoid {0001} using crystalline quartz as a charge; said growing being effected from aqueous solutions of sodium compounds selected from the group consisting of sodium carbonate and sodium hydroxide, said solutions having a concentration within the range of from 3 to 7 weight percent; said growing is effected at a crystallization temperature within the range of from 335° to 345° C. under a pressure of from 700 to 1,500 kg/cm 2 and a crystal growth rate of from 0.15 to 0.5 mm/day.
Claim 6
Dependent Claim
47 words
A process as claimed in claim 1, wherein the crystalline quartz seed plates are etched, prior to growing colorless quartz crystals, with a 40% hydrofluoric acid at a temperature within the range of from 18 to 22° C. for a period of from 2 to 3 hours.