The following text is for questions 5 to 8.

    Minerals are defined as solid, inorganic, naturally-occurring substances with a definite chemical formula and general structure. Almost all chemical elements in the Earth's crust are associated with at least one mineraL They vary in color, hardness, density, crystal form, crystal size, transparency, composition, location and abundance. Several minerals are radioactive (uranophane), while others are magnetic (magnetite). Several minerals are uncombined elements, such as gold, silver, sulfur, bismuth, copper, and platinum. Certain minerals glow with a vibrant luminescence after exposure to ultraviolet light, such as fluorite (calcium fluoride). Feldspar (a potassium aluminum silicate) and quartz (silicon dioxide) are the most abundant minerals found in the Earth's crust.

(Adopted from: http://www.geog.ucsb.edui-dylan/mtpe/ geosphere/topics/rx/minerals.html (April 5, 2020)

"Certain minerals glow with a vibrant luminescene" (Paragraph 2)

What is the synonym of the underlined word?