Abstract: The present invention relates to a photosensitive glass in which a Li2SiO3 crystal is precipitated by exposure and heat treatment, in which the photosensitive glass has a value of Formula (A) described below of 0.50 or more and 0.75 or less, and the photosensitive glass has a dielectric loss tangent at 20° C. and 10 GHz of 0.0090 or less, [Li2O]/([Li2O]+[Na2O]+[K2O]) Formula (A), in Formula (A), [Li2O], [Na2O], and [K2O] respectively indicate contents of Li2O, Na2O, and K2O in the photosensitive glass in terms of mole percentage based on oxides.

Abstract: The present invention relates to a circuit board for a high-frequency device, including: a glass substrate in which a crystal is precipitated and cuttable by etching, and which has a dielectric loss tangent at 20° C. and 10 GHz of 0.0090 or less, and relates to a high-frequency device including the circuit board.

Abstract: To provide a process for producing fine particles of crystalline oxide which have high crystallinity, are excellent in uniformity of the composition and particle diameter, and have a small particle diameter, and such fine particles of crystalline oxide. A process for producing fine particles of crystalline oxide, which comprises: a step of obtaining a melt containing an oxide of M (M is at least one member selected from the group consisting of Ce, Ti, Zr, Al, Fe, Zn, Mn, Cu, Co, Ni, Bi, Pb, In, Sn and rare earth elements (excluding Ce)) and B2O3, a step of rapidly cooling the melt to form an amorphous material, a step of pulverizing the amorphous material to obtain a pulverized material having a volume-based particle size distribution within a range of from 0.