delivered the opinion of the court:
Imported goods invoiced as spar prisms were classified by the collector of customs at the port of Rochester, N. Y., as articles composed wholly or in chief value of rock crystal and were accordingly assessed for duty at 50 per cent ad valorem under that part of paragraph 112 of the tariff act of 1909 which reads as follows:
112. * * * All articles composed wholly or in chief value of agate, rock crystal, or other semiprecious stones, * * * not specially provided for in this section, fifty per centum ad valorem.
The importer protested that the goods were in fact articles composed wholly or in chief value of earthy or mineral substances, and claimed that they were dutiable at 35 per cent ad valorem under the *417provisions of paragraph 95 of the tariff act of 1-909, which paragraph reads as follows:
95. Articles and -wares composed wholly or in chief value of earthy or mineral substances, not specially provided for in this section, whether susceptible of decoration or not, if not decorated in any manner, thirty-five per centum ad valorem; if decorated, forty-five per centum ad valorem; carbon, not specially provided for in this section, twenty per centum ad valorem; electrodes, brushes, plates, and disks, all the foregoing composed wholly or in chief value of carbon, thirty per centum ad valorem.
The protest was sustained by the Board of General Appraisers.
The merchandise in question is a crystalline substance having the form of an oblique prism, or solid, bounded by six quadrilateral planes, four of which constitute the sides and two the ends of the figure. All the side planes are parallel, and the two end planes make an oblique, angle with the planes constituting the sides. The appraiser returned the merchandise as spar prisms and certified that the sample in evidence was representative of so-called “nikols” or “glan thcmpson prismen.” It appears from an investigation of the standard authorities that nikols or Nicol prisms are the invention of William Nicol, a Scotch physicist, and are designed to increase the divergence of two rays of fight so as to produce a single image. (Encyclopedia Britannica.) To make the Nicol prism, a rhombóhedron of Iceland spar is first cut in two along a plane running from the lower fine of one end plane to the upper fine of the other. The two halves are then joined together by means of Canada balsam. (See Ganot’s Physics and Standard Dictionary.) Iceland spar belongs to the calcite group of minerals, and the calcites are carbonates of calcium. (Text book of Mineralogy, Dana, pp. 354-355.) The chemist to whom the merchandise was referred by the board for a report as to whether it was rock crystal, reported in writing that it Was “calcium carbonate crystal.” Bock crystal is a colorless or nearly colorless transparent quartz, and quartz is not a carbonate of calcium, but a dioxide of silicon. (See Bock Crystal and Quartz; Standard Dictionary; Textbook of Mineralogy, Dana, pp. 324-325.) From this it is apparent that the article imported is not rock crystal, and as it is not contended that it is either agate, which is a kind of quartz or a semiprecious stone, we think it clear that the merchandise should not have been classified for duty under paragraph 112. On the evidence submitted to the board, we find that the nikols or Nicol prisms are manufactured from the mineral substance known as carbonate of calcium, and as articles or wares of that class are not otherwise provided for, we must conclude that the importation jvas dutiable at 35 per cent ad valorem under the provisions of paragraph 95, as claimed by the importer.
The decision of the Board of General Appraisers is affirmed.