(I have always found the History of Middle-earth to be invaluable in writing stories)
"The Naugrim [Dwarves] were ever, as they still remain, short and squat in stature; they were deep-breasted, strong in the arm, and stout in the leg, and their beards were long. Indeed this strangeness they have that no Man or Elf has ever seen a beardless Dwarf - unless he were shaven in mockery, and would then be more like to die of shame than of many other hurts that to us would seem more deadly. For the Naugrim have beards from the beginning of their lives, male and female alike; nor indeed can their womenkind be discerned by those of other race, be it in feature or in gait or in voice, nor in any wise save this: that they go not to war, and seldom save at direst need issue from their deep bowers and halls. It is said, also, that their womenkind are few, and that save their kings and chieftains few Dwarves ever wed; wherefore their race multiplied slowly, and now is dwindling." (
HoME XI, The War of the Jewels. These are described as being the words of Pengolod, an elf of Gondolin in the First Age. There's no indication that he'd actually met any Dwarves)
"In their own tongue the Dwarves name themselves Khazâd; and the Dark-elves called them the Naugrim, the stunted. Which name the exiled Noldor likewise took for them..." (Same source)
It should also be noted that the race of Dwarves descending from Durin are called the Longbeards, 'for their beards swept the floor before their feet'. None of the other races of the Dwarves are known to be extant in western Middle-earth, but they do exist. More specifically, the Firebeards and Broadbeams may be extinct, having lived in the mountains of Beleriand before it sank. The Ironfists and Stiffbeards, Blacklocks and Stonefoots awakened much further east. (Summarised from
HoME XII: The Peoples of Middle-earth)
"Such dealings with their dead [burning the dead after the battle of Azanulbizar outside Moria] seemed grievous to the Dwarves, for it was against their use; but to make such tombs as they were accustomed to build (since they will lay their dead only in stone not in earth) would have taken many years. To fire therefore they turned, rather than leave their kin to beast or bird or carrion-orc. But those who fell in Azanulbizar were honoured in memory, and to this day a Dwarf will say proudly of one of his sires: 'he was a burned Dwarf', and that is enough." (
Lord of the Rings: Appendix A - Part III. Irrelevant, but a nice bit of lore)
"They [the Dwarves of the Blue Mountains, ie Thorin's people] had very few women-folk. Dís Thráin's daughter was there. She was he mother of Fíli and Kíli, who were born in the Ered Luin. Thorin had no wife." (Same source)
"Dís was the daughter of Thráin II. She is the only dwarf-woman named in these histories. It was said by Gimli that there are few dwarf-women, probably no more than a third of their whole people. They seldom walk abroad except at great need. They are in voice and appearance, and in garb if they must go on a journey, so like to the dwarf-men that the eyes and ears of other peoples cannot tell them apart. This has given rise to the foolish opinion among Men that there are no dwarf-women, and that the Dwarves 'grow out of stone'.
"It is because of the fewness of women among them that the kind of the Dwarves increases slowly, and is in peril when they have no secure dwellings. For Dwarves take only one wife or husband each in their lives, and are jealous, as in all matters of their rights. The number of dwarf-men that marry is actually less than one-third. For not all the women take husbands; some desire one that they cannot get, and so will have no other. As for the men, very many also do not desire marriage, being engrossed in their crafts." (Same source again)
Also from Appendix A:III, the largest attested family size is three children: Thráin II's two sons (Thorin II Oakenshield, Frerin) and one daughter (Dís).
"They are a tough, thrawn race for the most part, secretive, laborious, retentive of the memory of injuries (and of benefits), lovers of stone, of gems, of things that take shape under the hands of craftsman rather than things that live by their own life. But they are not evil by nature, and few ever served the Enemy of free will, whatever the tales of Men may have alleged. For Men of old lusted after their wealth and the work of their hands, and there has been enmity between the races." (
LotR: Appendix F)
"Dwarves of different 'breeds' vary in their longevity. Durin's race were originally long-lived (especially those named Durin), but like most other peoples they had become less so during the Third Age. Their average age (unless they met a violent death) was about 250 years, which they seldom fell far short of, but could occasionally far exceed (up to 300). A Dwarf of 300 was about as rare and aged as a Man of 100.
"Dwarves remained young - e.g. regarded as too tender for really hard work or for fighting - until they were 30 or nearly that (Dáin II was very young in 2799 (32) and his slaying of Azog was a great feat). After that they hardened and took on the appearance of age (by human standards) very quickly. By forty all Dwarves looked much alike in age, until they reached what they regarded as old age, about 240. They then began to age and wrinkle and go white quickly (baldness being unknown among them), unles they were going to be long-lived, in which case the process was delayed. Almost the only physical disorder they suffered from (they were singularly immune from diseases such as affected Men, and Halflings) was corpulence. If in prosperous circumstances, many grew very fat at or before 200, and could not do much (save eat) afterwards. Otherwise 'old age' lasted not much more than ten years, and from say 40 or a little before to near 240 (two hundred years) the capacity for toil (and for fighting) of most Dwarves was equally great." (
HoME XII: The Peoples of Middle-earth - 'The Making of Appendix A')
"
It is then said that Dwarves marry late, seldom before they are ninety or more, they they have few children (so many as four being rare), and continues:"To these they are devoted, often rather fiercely: that is, they may treat them with apparent harshness (especially in the desire to ensure that they shall grow up tough, hardy, unyielding), but they defend them with all their power, and resent injuries to them even more than to themselves. The same is true of the attitude of children to parents. For an injury to the father a Dwarf may spend a life-time in achieving revenge. Since the 'kings' or heads of lines are regarded as 'parents' of the whole group, it will be understood how it was that the whole of Durin's Race gathered and marshalled itself to avenge Thrór.
"
Finally there is a note on the absence of record concerning the women of the Dwarves:"They are seldom named in genealogies. They join their husbands' families. But if a son is seen to be 110 or so years younger than his father, this usually indicates an elder daughter. Thorin's sister Dís is named simply because of the gallant death of her sons Fili and Kili in defence of Thorin II. The sentiment of affection for sister's children was strong among all peoples of the Third Age, but less so among Dwarves than Men or Elves among whom it was strongest." (Same source. Italics indicate a comment or summary by Christopher Tolkien)
"
Baruk Khazâd! Khazâd ai-mênu!"
hS