The exquisite piece of linen thread bobbin lace to the left was created by hand sometime around 1690-1700 and might be called Baroque- even Rococo. This is a monstrance or benediction veil. What’s the difference between a monstrance and an ostensorium? Not much. Monstrance comes from the verb monstrare, “to show clearly”. You can see the word monstrance in the English word “demonstrate“.
Ostendere also means “to show” and the word as applied to the vessel used for exposition of the Blessed Sacrament is interchangeable with monstrance. A popular form this sacred vessel takes is a solar burst at the top of a vertical upright support, with many rays emanating from the central point, the place which contains the round luna, or lunette. This is a double glass or crystal lens set in a cylinder which contains a large priest host which has been consecrated. The lunette is easily removable, and usually each monstrance must have its luna custom-fitted. Monstrances and ostensoria (plural form) are made of the most precious materials affordable, and nearly always at the least gold-plated or sterling silver. Precious or semi-precious jewels are sometimes seen embedded around the lunette or in the base. When not in use, the lunette with the wafer inside may repose in a standing pyx inside the tabernacle. As the monstrance is waiting on the credence table or sacristy prior to the service, it must be covered with a white veil. Silk or handmade lace is preferred. It should completely cover the monstrance all around. The lace veil pictured above is 24 x 28 inches although each monstrance will have its own height measurements. Monstrances are sometimes constructed to look like miniature cathedrals, with Gothic spires and saints, or as a cross.
A corporal is generally spread on the center of the altar fair linen to receive the monstrance. I have seen some really beautiful benediction corporals in the state of Rhode Island. The white work with Eucharistic embroidery is worked on the finest batiste or fine linen. The corporal is of a generous size, and the burse used to carry it to the altar is sometimes slightly larger than the usual burse, and is always white, or white and gold. The monstrance will be handled with the humeral veil, once the Sacrament has been placed inside. Pockets are often provided at each end of the humeral veil for the hands to slip in. Several churches in the diocese have services of Benediction and observe Corpus Christi with a procession using the monstrance and baldicchino or canopy.