From BiblePortal Wikipedia

Hastings' Dictionary of the New Testament [1]

Alabaster ( ἀλάβαστρος or ἀλάβαστρον; in secular writers always ἁλάβαστρος [more correctly ἁλάβαστος], though with a heterog. plur. ἁλάβαστρα; in NT only in aecus, and only once with art., which is found in different MSS [Note: SS Manuscripts.] in all the genders—ΤήΝ , ΤάΝ , Τά [Tisch., Treg., WH [Note: H Westcott and Hort’s text.] , Meyer, Alford prefer ΤήΝ]).—The word occurs four times in the Gospels:  Matthew 26:7,  Mark 14:3 bis ,  Luke 7:37. The Oriental alabaster, so called from the locality in Egypt (the town of Alabastron, near Tell el-Amarna)* [Note: The reverse supposition is possible, that the town derived its name from the material (see Encyc. Bibl. i. 108).] where it is found in greatest abundance, is a species of marble softer and more easily worked than the ordinary marble. It was so frequently used for holding precious ointment that ἁλάβαστρος came to be a synonym for an unguent box (Theoer. xv. 114; Herod. iii. 20), Horace ( Od. iv. 12. 17) uses onyx in the same ways.

In all three of the Gospel narratives emphasis is laid on the costliness of the offering made to our Lord. The ointment was that with which monarchs were anointed. Judas valued it at three hundred pence. If we bear in mind that a denarius was a day’s wage for ordinary labour, it would represent about four shillings of our money. And unguent and box would have a value of something like £60. Mary ‘brake the box.’ This is generally interpreted as merely meaning ‘unfastened the seal’; but is it not in accordance alike with a profound instinct of human nature and with Oriental ideas to interpret the words literally? The box which had been rendered sacred by holding the ointment with which Jesus was anointed would never be put to a lower use.

This incident is the gospel protest against philanthropic utilitarianism. ‘Man shall not live by bread alone, but by every word that proceedeth out of the mouth of God.’ We have here the warrant for the expenditure of money on everything that makes for the higher life of man. Whatever tends to uplift the imagination, to ennoble and purify the emotions, to refine the taste, and thus to add to the spiritual value of life, is good, and is to be encouraged. Jesus claims our best. He inspires us to be and do our best, and the first-fruits of all the higher faculties of the soul are to be devoted to Him. See, further, art. Anointing i. 2.

A. Miller.

Smith's Bible Dictionary [2]

Alabaster. From the Arabic 'al bastraton' , A Whitish Stone or from Alabastron , the place in Egypt where it is found. It occurs only in  Matthew 26:7;  Mark 14:3;  Luke 7:37. The ancients considered alabaster to be the best material in which to preserve their ointments. The Oriental alabaster (referred to in the Bible) is a translucent carbonate of lime, formed on the floors of limestone caves by the percolation of water.

It is of the same material as our marbles, but differently formed. It is usually clouded or banded like agate, hence, sometimes called onyx marble. Our common alabaster is different from this, being a variety of gypsum or sulphate of lime, used in its finer forms for vases, etc.; in the coarser, it is ground up for plaster of Paris. The noted sculptured slabs from Nineveh are made of this material.

Watson's Biblical & Theological Dictionary [3]

‘Αλαβαστρον , the name of a genus of fossils nearly allied to marble. It is a bright elegant stone, sometimes of a snowy whiteness. It may be cut freely, and is capable of a fine polish; and, being of a soft nature, it is wrought into any form or figure with ease. Vases or cruises were anciently made of it, wherein to preserve odoriferous liquors and ointments. Pliny and others represent it as peculiarly proper for this purpose; and the druggists in Egypt have, at this day, vessels made of it, in which they keep their medicines and perfumes.

In  Matthew 26:6-7 , we read that Jesus being at table in Bethany, in the house of Simon the leper, a woman came thither and poured an alabaster box of ointment on his head. St. Mark adds, "She brake the box," which merely refers to the seal upon the vase which closed it, and kept the perfume from evaporating. This had never been removed, but was on this occasion broken, that is, first opened.

People's Dictionary of the Bible [4]

Alabaster. What is usually called alabaster is a kind of soft gypsum, properly sulphate of lime. But the alabaster of which jars and vases were usually made was finer grained, opaque, and usually white, but frequently shaded with other soft colors; hence sometimes called onyx marble, which is properly a carbonate of lime. Several vases of alabaster have been found in Egypt, varying in form and size; one of which, bearing the name and title of the queen of Thothmes II., had ointment in it, which had retained its odor for several centuries. In  Mark 14:3 the phrase "she brake the box," is simply, "she brake the alabaster," I.E., the vase so called; and merely refers to the breaking of the seal which closed the vase, and kept the perfume from evaporation.  Matthew 26:7;  Luke 7:37.

American Tract Society Bible Dictionary [5]

A sort of stone, of fine texture, either the white gypsum, a sulphate of lime, or the onyx-alabaster, a hard carbonate of lime, having the color of the human nail, and nearly allied to marble. This material being very generally used to fabricate vessels for holding unguents and perfumed liquids, many vessels were called alabaster though made of a different substance, as gold, silver, glass, etc. In  Matthew 26:6,7 , we read that Mary, sister of Lazarus,  John 12:3 , poured as alabaster box of precious ointment on Christ's head. Mark says "she brake the box," signifying probably, that the seal upon the box, or upon the neck of the vase of bottle, which kept the perfume from evaporating, had never been removed; it was on this occasion first opened. See Spikenard .

King James Dictionary [6]

AL'ABASTER, n. L. from Gr.

A sub-variety of carbonate of lime, found in large masses, formed by the deposition of calcarious particles in caverns of limestone rocks. These concretions have a foliated, fibrous or granular structure, and are of a pure white color, or more generally they present shades of yellow, red or brown, in undulating or concentric stripes, or in spots.

Among the ancients, alabaster was also the name of a vessel in which odoriferous liquors were kept so called from the stone of which it was made. Also, the name of a measure, containing ten ounces of wine or nine of oil.

AL'ABASTER, a. Made of alabaster, or resembling it.

Alabastrum dendroide, a kind of laminated alabaster, variegated with figures of shrubs and trees, found in the province of Hohenstein.

Webster's Dictionary [7]

(1): (n.) A hard, compact variety of carbonate of lime, somewhat translucent, or of banded shades of color; stalagmite. The name is used in this sense by Pliny. It is sometimes distinguished as oriental alabaster.

(2): (n.) A box or vessel for holding odoriferous ointments, etc.; - so called from the stone of which it was originally made.

(3): (n.) A compact variety or sulphate of lime, or gypsum, of fine texture, and usually white and translucent, but sometimes yellow, red, or gray. It is carved into vases, mantel ornaments, etc.

Fausset's Bible Dictionary [8]

Not our gypsum, but the oriental alabaster, translucent, with red, yellow, and gray streaks clue to admixture of oxides of iron with a fibrouscarbonate of lime. A calcareous marble like spar, wrought into boxes or vessels, to keep precious ointments from spoiling (Pliny H. N., 13:8).  Mark 14:3; "broke the box," i.e., broke the seal on the mouth of it, put there to prevent, evaporation of the odor ( Luke 7:37).

Morrish Bible Dictionary [9]

A valuable calcareous spar, a hydro-sulphate of lime, used by the ancients for making vessels to hold valuable ointments. It is probable that 'breaking' ' the box means breaking the seal, to open the box.  Matthew 26:7;  Mark 14:3;  Luke 7:37 .

Easton's Bible Dictionary [10]

 Matthew 26:7 Mark 14:3 Luke 7:37 Matthew 20:2

Holman Bible Dictionary [11]

Minerals And Metals

Hastings' Dictionary of the Bible [12]

ALABASTER . See Jewels and Precious Stones.

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [13]

Kitto's Popular Cyclopedia of Biblial Literature [14]